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B/ArxRlClILTURAL ENTOM( )I.O(IY

FOR STUDENTS, FARMERS, FRUIT-GROWERS
AND GARDENERS '

BY

HERBERT OSBORN, B.Sc, M.Sc.

'ROFESSOR OF ZOOLOGY AND ENTOMOLOGY IN THE OHIO STATE UNIVERSITY,

COLUMBUS, OHIO, AND DIRECTOR OF THE LAKE LABORATORY,

CEDAR POINT, OHIO.

ILLUSTRATED WITH 252 ENGRAVINGS AND A COLORED PLATE

LEA & FEBIGER

PHILADELPHIA AND NEW YORK
1916

Entered according to the Act of Congress, in the year 1916, by

LEA & FEBIGER,
in the Office of the Librarian of Congress. All rights reserved.

PREFACE.

Tfiis book is designed to meet the needs of students and
others who wish to learn something of insect Hfe especially
in relation to farm crops and livestock. The author assumes
that the students who read it will have had some training
in general biology and will have the guidance of teachers
familiar with the subject in connection with adequate labor-
atory facilities and opportunities for field studies. The
details of laboratory and field studies have not been included
since these are easily supplied by the teacher. For those
making individual studies there are many available books
covering the technic of entomological work. A glossary
has been included which covers the subject as presented in
these pages and in most of the reports and bulletins that are
likely to be consulted by the average student.

In order to make the scope of the book adequate it has
been necessary to condense the matter to the most essential
details, and to omit much that has value but which is not
absolutely indispensable to the presentation of the important
principles that concern the practice of economic entomology.

The author acknowledges his indebtedness to many
sources of information which are too numerous to mention
individually, but he is especially indebted to Dr. Howard,
of the Bureau of Entomology, for the privilege of using the
illustrations secured from his office and for suggestions; to

iv PREFACE

Professors Washburn and Brunc^r for the loan of plates;
to the Iowa Experiment Station for use of figures, and the
Ohio Experiment Station for a number of photographs for
original use here. Professors Hine, Metcalf, Barrows,
Mr. Kostir and Mr. Drake have assisted in reading manu-
script and proof and have generously given the author
the use of photographs and drawings.

H. O.
Columbus, Ohio, 191G.

CONTENTS

CHAPTER I.
Introduction 17

CHAPTER II.
Class Arachnida 22

CHAPTER III.

The Six-footed Insects 38

CHAPTER IV.

Lower Pterygota 51

CHAPTER V.
Order Hemiptera 93

CHAPTER VI.

Neuroptera and Allies 165

CHAPTER VII.

Coleoptera. Beetles 172

CHAPTER VIII.

Lepidoptera 2U()

CHAPTER IX.

Order Diptera 248

CHAPTER X.
Bees and Wasps 291

CHAPTER XI.

Principles of Economic Entomology 312

Glossary ;j29

Index 339

AGKICULTUEAL ENTOMOLOGY.

CHAPTER I.
IXTUODUCTIOX.

The recent rapid growtli in the subject of Agricultural
Entomology makes it a difficult matter to bring together
a comprehensive statement that will cover all of its different
phases in a thorough manner. Some idea of its growth
may be indicated by the fact that instead of a single ento-
mologist employed in the United States Department of
Agriculture, as was the case forty years ago, there are now
several hundred who are devoting their entire time to the
investigation of entomological problems, practically all of
which are related to agriculture.

A similar development of this work has taken place in
the State Experiment Stations, and there are also State
^Entomological departments working in almost every State,
and in many of them two or three different organizations,
each with a large quota of workers.

Economic entomology in its wider sense covers all those
phases of the subject which have to do with insects of
importance in relation to mankind. The forms which
have distinctly agricultural relation are so numerous and
represent so completely all the different groups of insects
that we are compelled to include a very general survey of
the subject.

Some idea of the size of the grouj) of insects and of its
place in biological study may be secured from the statement

(17)

18 INTRODUCTION

that there are now known and have been scientifically recog-
nized and described something over three hundred thousand
species of insects, a number which far surpasses that of all
other groups of animals together. Furthermore, the immense
numbers of individuals in each species and the great facility
which they possess for migration and rapidity of increase
make them a very dominant group of animals.

Not all insects, to be sure, have a direct importance to
mankind, but there is so large a number that are very
directly related to human interests in the way of destruction
of property or menace to health that it is unnecessary to
emphasize their importance. Many estimates have been
attempted of the extent of loss of crops, livestock, forests,
agricultural products, etc., and while none of these can be
considered exact, it is increasingly evident that such estimates
are conservative and in many cases the loss is greater than
is recognized. One of the current estimates is that about
10 per cent, of the aggregate of farm crops in the United
States is lost by insect attack, and if this be taken as an
approximate proportion there is something like one billion
dollars to be counted an economic loss from this source
each year.

It must be admitted that the entomologist has not been
able as yet to solve all of the problems of insect control.
There will doubtless be many cases where a practical control
of insects may not be reached for many years, but for a
considerable number of the most common and serious pests
it has been possible to discover methods by which a very
large proportion of the loss can be prevented. One phase
of entomological work, therefore, is the demonstration of
these possibilities in order to secure a general adoption of
control measures that have been proved successful.

While it is manifestly impossible to include in a small
book any full discussion of the many phases of entomology,
it is the purpose of this work to present a basis for the under-
standing of field observations, and especially for the under-
standing of the many articles relating to economic insects
which are now appearing in Government and State pub-

INTRODUCTION 19

lications. Many of these publications are available and will
be found to contain an immense store of information, much
of it of very practical value, but its greatest utility will be
found to rest upon some acquaintance with the general
facts of insect life and insect habits. These are so dependent
upon certain conditions of structure and development that
acquaintance with some of the fundamental biological
features of insect life are essential to the most effective
utilization.

Formerly all of the arthropods, that is, all animals with
jointed bodies and jointed appendages, were grouped under
the head of insects, and even yet this term has a pretty
wide application in popular usage, although it is seldom
used now to cover as wide a range as formerly. The Arth-
ropods, as a whole, include crustaceans, myriapods, arach-
nids, hexapods, or^ six-footed insects, and of these the air-
breathing forms, all except the crustaceans, are still quite
commonly treated as insects.

The Onychophora is a tropical group including peripatus,
the most primitive of tracheate animals, and would on this
basis be considered as falling next to the Crustacea.

The most generalized next to these, the myriapods, might
be counted as possessing the greater number of insect-like
characters. This group, however, does not include any
forms that possess wings, but in the matter of antennse and
the tracheal respiration they are closely associated with
insects. The members of this group are, for the most part,
of comparatively little economic importance. A few of the
species included in the group of centipedes {Chilopoda) are
poisonous, and in tropical countries are of some importance
on this account. The few species that occur in temperate
regions have little importance except as they may feed upon
other insects which occur under the litter at the surface of
the ground.

One species, the house centipede, a peculiar long-legged
creature, which is occasionally found in cellars or around
houses, usually where there is some dampness, is, however,
of a certain amount of importance because of its feeding

20

INTRODUCTION

upon insects, and is looked u})on as rather serviceable in the
destruction of flies. It is a quite inigainly looking creature,

Fig. 1. — Sculigcra forceps: Adult — natural size. (From Marlatt,
Div. Ent., U. S. Dept. Ag.)

with slender, flattened body, extremely long legs, and an
apparent duplication of anterior and posterior ends.

The millipedes ( Diplopoda) are nearly cylindrical in

INTRODUCTION 21

shape, are recognized as having two pairs of legs to each
apparent segment and there is usually a large number of
segments, 40 to 100 or more, so that the name thousand-

FiG. 2. — Scutigera forceps: a, newly hatched individual; b, one of the
legs of same; c, terminal segment of body showing undeveloped legs coiled
up within — ail enlarged. (After Marlatt. Div. Ent., U. S. Dept. Ag.)

worm is fairly descriptive. Most of these species
are found in moist places and feed upon vegetable debris,
but a few have been recorded as attacking vegetation, and
one species has been credited with injuring seed corn.

CHAPTER II.
CLASS ARACHNIDA.

In the strict teclmical sense the group Arachnida may be
exckided from the Insecta, but in general usage, and to a
large extent in entomological practice, these divisions are
put together, and it seems desirable that the group should
be given a place in any work dealing with the insects in
general.

The group Arachnida includes spiders, scorpions, harvest-
men, mites, ticks, etc., and is characterized by the presence
of four pairs of legs, the absence of antennse and compound
eyes,^ and the lack of distinct metamorphosis, although
in certain groups there is a considerable change from the
newly hatched or six-legged form to the mature eight-legged
stage.

In general structure the Arachnida agree with other
Arthropoda, but the head and thorax are usually merged
into a cephalothorax separated from the abdomen by a
more or less distinct stalk; in the Acarina, however, this
separation is not marked and the body is without distinct
separation of head, thorax, and abdomen.

The economic importance of the group depends upon
their attacks upon certain crops, from the fact that many
of the species, such as spiders and harvestmen, are uniformly
predaceous and serve as important checks upon injurious
species; while other forms, such as the mites and ticks, are
parasitic upon domestic animals and man, and some of the
species occupy a most important relationship as carriers
of infectious diseases.

The subdivisions of the group are, for the most part, very
well marked and represent ancient groups which have
diverged quite widely from each other.

The scorpions (Scorpionida), mostly tropical in distribu-
(22)

CLASS ARACHNIDA 23

tion, are represented by fossils in early geological times,
and are noted as possessing poison glands. They are recog-
nized by the broad cephalothorax, a division of the abdomen
into two portions, an anterior preabdomen of seven seg-
ments, and a slender hinder postabdomen of six segments,
on the last one of which there is a large poison gland and
sting. The sting is distinctly venomous and fatal to insects
or smaller animals, but seldom serious in it's effect on the
human species.

The Pseudoscorpionida are minute forms resembling
scorpions in the width of the body and the long pedipalps,
but have no postabdomen or sting. They occur somewhat
commonly under bark or decaying logs or occasionally in old
papers or books, where they may secure book lice as food.

The Pedipalpi, or whip scorpions, have a tropical or
subtropical distribution and differ from the preceding groups
in the presence of a long, slender bristle or whip extending
from the hinder abdominal segment.

In the group Solpugida there is an exceptional separation
of head and thorax and the abdomen is distinctly segmented,
while the chelicerai are greatly enlarged and strongly chelate.
These are not only largely tropical, but are particularly
characteristic of arid regions. One species occurs in the
Rocky Mountain region as far north as Colorado. They
are carnivorous in habit, but not of particular economic
importance, as they occur usually in small numbers and in
locations which do not offer opportunity to capture espe-
cially injurious insects.

The Phalangida, or harvestmen, often called "daddy-
longlegs," are somewhat large and resemble spiders in
appearance, but the abdomen is not distinctly separated
from the thorax and the legs are in most species extremely
long. They feed on insects, especially on flies and other
small forms, and are to be counted as distinctly beneficial.
On account of a strong pungent odor they are disagreeable
to handle, but their presence in gardens and other places
where insects abound may be considered as distinctly desir-
able.

24 CLASS ARACHNIDA

Order ARANEIDA.

This group includes tlie familiar spiders which are very
generally distributed over the world, and occupy a rather
conspicuous ])lace among other animals. Their body is
sharply dixided into cephalothorax and abdomen, and the
four j)airs of legs nrv usually nearly ec|ual in length. The

Fig. 3. — Epeira scohpeturia, showing iiornuil position of spider in web
head downward. A vibrator at .t agitating the web will cause the spider
to rush at once to point of contact. (Photo by Prof. W. M. Barrows.)

eyes are sim])le and usually eight in numl)er, and the large
mandibles are attached at right angles to the axis of the
body. In some species these are provided with a poison
duct. The bite is venomous to smaller organisms, and in
some of the larger, like the tarantula, the bite is a serious
matter for man. Sj^iders offer a great many attractive

ORDER ACARINA

25

features, particularly in their web-making habit and in their
achiptation for the cajrture of prey. They are distinctly
carnivorous in habit and may be considered useful, since
the majority of them capture insects, and the kinds of
insects captured are quite generally such as are detrimental
to man. In general, therefore, spiders sliould be left unmo-
lested and their insect-feeding habits utihzcd in the reduc-
tion of injurious insects.

Fig. 4. — The common red spider (Tetranychus himaculatus) : a, adult;
h, palpus; c, claws; n, greatly enlarged; h, c, still more enlarged. (After
Banks. From Bur. Ent., U. S. Dept. Ag.)

Order ACARINA.

These are commonly known as mites, ticks, scab insects,
mange insects, etc., and are in general distinguished by
having no prominent separation between the different
regions of the body, the head, thorax, and abdomen, forming
one closely connected structure. They haxe eight legs,
except in the early stages, when there are but six; the
eyes are often small or obsolete, the spiracles reduced to
one pair, sometimes apparently wanting; the moutli parts

26 CLASS ARACHNIDA

are fitted for piercing, biting, or in some cases for combined
biting and suction, there being usually a pair of slender,
sharp mandibles capable of penetrating the skin of the
host animals. Much variation of habit exists, and ranges
from free forms to strictly parasitic forms.

Fig. 5 — Tetranychus gloveri: Adult — much enlarged, (Titus, Div.
Ent., U. S. Dept. Ag.)

Harvest Mites; Chiggers.

In the family Tromhidiidoe, which includes normally plant-
feeding species, we find a few species which have adopted
a phase of parasitism which, though apparently abnormal,
results in extreme annoyance to the animals affected.

Apparently the most abundant species in this country
is the Leptus irritans of liiley, which is illustrated herewith.
This occurs in a large portion of the United States, and
occasions during the summer months an enormous amount
of suffering. It ranges north in the INIississippi Valley into

ORDER ACARINA 27

central Iowa, at least, and in Ohio to Lake Erie, appearing
by the latter part of June or fore part of July, but becoming
especially annoying during August. In the latitude of
Washington it is very abundant early in June, and farther
south its season extends until, in southern Mexico, what
is apparently the same species is abundant and equally
annoying in January.

The form in which this pest is observed usually is the
larval or six-legged form. It is nearly circular in outline,
the legs extending well beyond the margins of the body,
of a bright red color, and so minute that it is only with
the closest scrutiny that it can be detected.

Fig. 6. — Leptus irritans to the right and amcricana to the left. (From
Riley.)

It is brushed from the leaves of various plants on to the
hands or clothing of people and to the bodies of other animals,
and the mite then proceeds to burrow into the skin, not-
withstanding the fact that, so far as all evidence shows,
this proceeding is absolutely fatal to it and prevents any
possibility of its maturing or producing eggs.

There is great difference in the susceptibility shown by
different persons to the attacks of this mite, some not
seeming to be affected seriously by them, while others must
submit to extreme torture every time they happen to become
attacked bv them, even if but few in number.

28 CLASS ARACHNIDA

As the mites are invariably secured by working ainono;
raspberries, currants, or other shrubbery which liarbors
them, or by walking in grass or low herbage where they
occur, sometimes even by sitting or lying for a short time
upon grass or clover, it is evident that the best precaution
for susceptible persons is to avoid all such exposure. When
such a\-oiflance is impracticable, the clothing may l)e made
to fit closely at the wrists and ankles, and then as soon as
possil>le after having been exposed to the mites make an
entire change of clothing, bathe in hot, soapy water, and
if any indications of mites are present, wash the affected i)arts
with diluted carbolic acid, 1 part to 50 or 100 parts water.

In the tropics rum or whisky is recommended as a wash,
and diluted alcohol can be used with good results.

\Yith a little pains it is possible to locate the mites, as
they may be found before they have completely buried
themselves in the skin in the centre of the little red swelling
that has been raised by their preliminary irritation, and if
they are removed at this stage, instead of being allowefl to
bury themselves in the skin the subseciuent inflammation
and itching will be largely prevented.

Family Gamasidae. — The family Gamasidcp contains a
large numl)er of small mites, most of them being free or
semiparasitic in habit.

A large number occur as parasites on various species of
insects, but the two species to be mentioned here occur on
birds, and are sometimes very troublesome.

The Bird Tick {Dermanyssus avium). — The bird tick is a
very familiar form to keepers of cage birds, and is known in
many places as the redjnite. It occurs on a great variety
of birds, and has sometimes been considered to embrace
the chicken tick, mention of which follows, but that is
now generally conceded to represent a distinct form. The
mites are easily seen with the naked eye and appear as
animated red specks running over the bodies of birds, or
on the perches, bars of cages, etc. The eggs are laid in
cracks or corners of the cage, where may be found also the
molted skins and often numerous young and old mites.

ORDER ACARINA

29

The attacks on the birds are made probably for the
most part at night, but the mites are usually well filled
with blood, which gives them their red color.

The use of perclies that are solid, smooth, and free from
cracks, and the frequent dipping of these in liot water, and-
the thorough cleansing of the entire cage, using boiling water
if there are inaccessible cracks, will serve to destroy the
pests.

Fig. 7. — Poultry tick (Derrnanyssus gallinw): a, adult; h, tarsus; c,
mouth parts; d and e, young — all enlarged. (After Osborn, Bur. Ent., U.
S. Dept. Ag.)

The Poultry Tick {Derrnanyssus g all iiicp).— One of the
most ])crsistent and injurious of the pests of the hennery
is the little chicken mite, which gathers on the fowls, espe-
cially at night, and sucks their blood. It is a well-known
form, and has been described for many years, though in
many works it is confused with the preceding species or
considered simply a variety of that form. Its distribution
seems to extend pretty generally over the world where
domestic fowls are kept.

30 CLASS ARACHNIDA

The full-grown mites are about 1 mm. long, of a light
gray or whitish color, with dark patches showing through
the skin, but when full fed have a distinct red color. They
swarm in cracks and corners of the henhouse, and often
when numerous, over all surrounding objects, and at such
time are liable to become a great pest to man and such other
animals as they may get access to.

The dust bath is considered of use in checking this pest,
but when there is a general infestation, the best plan will
be found to clear the house, then spray well with kerosene
or kerosene emulsion, taking pains to reach the cracks;
thoroughly drench the roosts with hot water or kerosene,
benzine, or gasoline, whitewash the house, or dust with
carbolated lime, and then daub the ends of the roosts, where
they come in contact with supports, with coal tar, so the
mites would have to cross it to reach the fowls.

Family Ixodidse. — This family includes forms known
commonly as ticks, and familiar examples are the dog tick
or wood tick, frequently found upon domestic animals,
and other examples are the cattle tick of the Southern States
and spotted fever tick of the Rocky Mountain region. In
this group the body is robust and becomes much distended
in the female when the eggs are developed. The mouth
parts are adapted for puncturing the skin of host animals,
and the species generally attach themselves to warm-blooded
animals as a part of the life-cycle, and in some cases this
attachment is permanent, while in others it is temporary
and the individual tick may occupy several different hosts
in the com-se of its life-cycle.

The family is of particular importance because of the
fact that some of the species are carriers of important
diseases, most notable of which is Texas fever, transmitted
by the cattle tick. The spotted fever tick is the carrier of
s])()tted fever.

The Pigeon Tick (Aryas rcflexus). — The i)igeon tick is a
common species on pigeons found mainly in pigeon houses,
and sucks the blood of pigeons for its nutriment. It is,
however, able to survive for long periods without food,

ORDER ACARINA

31

some recorded instances are of individuals kept in confine-
ment for two years without food, but which moulted at
frequent intervals.

The related Argas persicus occurs both in the old world
and America. It is a troublesome pest for chickens and is
credited also with attacks on human beings.

Fig. 8. — Argas ?iiinialus. a tick which infests poultry. Greatly enlarged.
(Banks, Div. Ent., U. S. Dept. Ag.)

The Cattle Tick (Margaropus annulatus). — The cattle tick,
as already mentioned, has received probably more atten-
tion than any other species, as it has been known for many
years as the carrier of Texas fever in cattle, and its great
importance to the cattle industry has been the occasion
for elaborate studies regarding its habits. In this species
the newly hatched tick locates as soon as possible upon
a warm-blooded animal, preferably upon cattle, as these
seem to be by all means the preferred host. Once located
they retain their attachment until mature. The females
when mature and gorged with eggs loosen their hold, drop
to the ground and eggs may be distributed wherever the
adults fall. The period of incubation differs greatly with
regard to temperature, so that the rate of development and
number of generations differ much at different seasons of

32 CLASS ARACHNIDA

the year. An important fact concerning the transfer of
disease is that the protozoa in the diseased animal are taken
into the body of the tick, and within the body of this host
may enter the eggs, so that young ticks that have never fed
upon an animal may serve to introduce the parasite in an
individual that has not previously had the disease.

Elimination of ticks from the cattle and prevention of
their attacks therefore become essential factors in the
eradication of Texas fever. To accomplish the eradica-
tion of the ticks in any given locality it is necessary to
rotate animals from one field to another, allowing time for
hatching of eggs and dying of the ticks before the field again
is used as a pasture for cattle. Working upon this basis,
considerable areas in the Southern States are now con-
sidered tick-free and the hope is that the quarantine line
will be pushed farther and farther south until ultimately'
the ticks and associated disease may be completely eradi-
cated. Certain districts in Tennessee and North Carolina
are now considered tick-free and released from quarantine
restrictions.

The Spotted Fever Tick {Dcrmaccntor venusta). — The
spotted fe\er tick has come into great prominence in recent
3'ears because of the determination that it serves as the
carrier of the much-dreaded spotted fe^•er. This disease
has caused many deaths in Montana and adjacent States,
and the rate of mortality for individuals attacked is very
high, so that its appearance is very much dreaded.

It has been shown that this disease is carried by this
particular species of tick, and in no other way. It differs
in habit from the cattle tick in that a number of different
hosts may be fed upon at different periods in its de\'elop-
ment. Usually the young larvse attach themselves to ground
squirrels or smaller mammals and remain upon these from
three to five days, after which they drop to the ground.
After a resting period of from one to three weeks the skin
is moidted and an eight-legged form appears, which in turn
attaches itself to some host and feeds for several days,
dropping to the ground and developing into the adult

ORDER ACARINA

33

Fig. 9

Fig. 10

§

P^IG. ]

Fig. 12

Figs.

Fig. 1.3 Fig. 14

to 14. — The spotted fever tick (Dermacentor vcnustus and Derma-

centor albipictuH). (Hunter and Bishopp.)
Fig. 9, adult spotted fever tick which has deposited eggs. Fig. 10, larva
of spotted fever tick. Fig. 11, engorged nymph of spotted fever tick.
Fig. 12, the same, ventral view. Fig. 13, adult male of Dermacentor nlhi-
piclus. Fig. 14, adult female of Dermacentor alhipicliis, unengorged.
3

34

CLASS ARACHNIDA

stage. In the adult stage still another host is sought, this
time usually some of the larger animals, such as domestic
cattle or sheep, and i)r()bably in the wild condition such

Fig. 15. — Psoroptes communis, var. cgui. (Reduced from Furstenberg,
after Murray.)

animals as the antelope or Rocky Mountain sheep or other
ruminants of the Rocky Mountain region. On these hosts
fertilization occurs and the females then drop to the ground

ORDER ACARINA 35

where the eggs are laid and a new cycle begun. The disease
has some remarkable limitations in its distribution which
are probably associated with the distribution of the ticks or
the animals which serve as a reserve for the disease germs.

Family Sarcoptidae. — This family includes parasitic mites,
affecting particularly birds and mammals.

The Sheep Scab Mite (Psoroptes communis, var. ovis). —
The sheep scab mite produces a very serious condition
among sheep, evidenced by matting and tagging of wool
and the formation of thick, encrusting scabs. The eggs of
this mite are minute, glistening white specks, longer than
broad and nearly uniform in thickness. They may be
found under the scabs by careful inspection, and their
detection, even when mites are not seen, may be taken as
evidence of the disease.

The larvse have nearly the same shape as the adults, but
are to be distinguished by the fact that only six legs are
apparent.

The full-grown mites are nearly as broad as long, and are
characterized by their piercing mouth parts and the struc-
ture of the two posterior pairs of legs (see Fig. 15). In the
male the fourth is much reduced, and the third bears a
long thread-like appendage passing the sucker, while in
the female this leg carries two long, thread-like organs and
no sucker.

The only treatment for this species worthy of recognition
is that of dipping, and this, if properly done, will secure the
extermination of the pest. A flock once freed will not
become again infested except by exposure to infected animals
or by the introduction of scabby individuals.

So important is this parasite deemed that many of the
States have adopted stringent laws for the quarantine of
infected animals and for prescribing dips that must be used.

The particular kind of dip is of less importance than the
thorough use of the one selected. The tobacco dips, sulphur
and lime dips, and also several of the patent dips prepared
by reputable firms can be recommended. The main objec-
tion to the latter, perhaps, is the fact that the user must

36

CLASS ARACHNIDA

pay a rather exorl)itant price for a few simple chemicals,
and further, in case of the arsenical dips, that he may not
know the ingredients or their proportions and thereby endan-
ger tlie animals treated.

The Itch Mite. — The itch mite, or "itch insect," afl'ecting
man is perhaps becoming a rather rare pest in civilized
communities, but since it occurs at times on domestic
animals, and in certain varieties becomes at times a serious
pest to such animals, it deserves mention here. Authors

Fig. 16. — Sarcoptes scabiei: male and female. (Reduced from
Furstenberg, after Murray.)

have differed greatly in their treatment of the species, some
making a different species for each host animal, believing
that they could find distinctive characters in the size,
arrangement of spines, etc.; but recent authors have com-
bined most of these under the one species, scabiei, though in
some cases retaining the varietal distinction for various
hosts.
All stages of the parasite occur on the host upon which

ORDER ACARINA , 37

it is absolutely dependent for existence. Generation after
generation may occur on the same animal. The mite
burrows under the skin, in tliis respect differing from scab
mites.

The adult mites are flattened, rather circular in outline,
and may be separated from related forms by the character
of the feet and by the presence of six short spines or thorns
on the thoracic portion anfl fourteen on the abdominal
portion of the body.

Eggs are deposited along the burrow as the mite extends
its channel into the deeper portions of the skin, and as they
hatch the young feed upon the surrounding tissues, and it
is said moult four times before maturity. When fully grown
they wander around and mate on the surface of the skin,
after wdiich the females begin a fresh burrow.

Infection with this parasite is accompanied by intense
itching during the formation of pustules and inflamed areas,
and while in man it is usually confined to the base of the
fingers and between the knuckles, in aggravated cases the
whole hand and arm may become invaded.

The "seven-year itch," "army itch," and "Jackson itch"
are simply aggravated cases, where from lack of good sani-
tation the mites are able to thrive better than usual.

In the human subject the application of sulphur ointment,
in addition to frequent washing with soap and hot water,
and for domestic animals the use of washes and dips, as for
scab mites, are to be adopted.

CHAPTER III.
THE SIX-FOOTED INSECTS.

The Ilexapoda, or the true insects, inchule those forms
with three pairs of legs, and the group is further distin-
guished from the other tracheate forms by hxrge compound
eyes and for a considerable portion of the group the presence
of one or two pairs of wings.

Of the various arthropods this division includes by far
the greater number of species and to a large extent those
forms which have the greatest agricultural importance.

STRUCTURE OF INSECTS.

There are some details in the structure of insects that
have a special importance in connection with the use of
remedies and some that from their frequent use in the
description of injurious species require explanation as a
basis for proper understanding of these principles. These
will be treated here as briefly as may be, bearing in mind
constantly this main issue in their presentation.

The insect body is divided into three regions, head, thorax,
and abdomen. The first appears to be one solid segment,
though believed fundamentally to consist of six or seven
segments closely fused together. The thorax has three
segments usually pretty closely joined, while the abdomen
possesses from three to nine visible segments, and these
articulate so as to be free to move on each other.

The head bears appendages, a number of definite struc-
tures connected with sensation or nutrition, and which are
of special service in separating the different groups of insects.
The antennse are jointed appendages usually situated on
the upper and front part of the head, composed of a varying
(38)

STRUCTURE OF INSECTS

39

number of segments and modified in a great variety of ways
in different groups of insects. Some of these modifications
may be mentioned briefly.

The joints may be widened so as to appear toothed along
one margin, in which case they are called serrate. If con-
stricted at each end so as to appear like a string of l)eads
they are called moniliform; if expanded widely toward the
apex on one side they form a series of comb-like teeth and
are then said to be pectinate; if swollen toward the apex,
or club-shaped, they are called clavate; and if this swollen
portion is confined to a few of the terminal segments and
expanded so as to form a ball they are capitate. In moths

C"^" 8^^^ Pall/us
Laliium Maxilla

Prulhurax [lead

Fig. 17. — Anatomy of grasshopper. (Reduced from Packard.)

they may be provided with a series of plume-like expansions
on either side and are then bipectinate, or if extremely wide
and feathery are called plumose.

The compound eyes are usually large and conspicuous,
and composed of an immense number of facets, these num-
bering in some insects many thousands, being especially
numerous in dragon flies, horse flies, and some butter-
flies. The ocelli are the more simple eyes, composed of a
single lens, and are often so minute as to be seen with diffi-
culty except by the aid of a lens. They may be three in
number, sometimes two and in some cases wanting. Usually
they are located between the compoimd eyes, and on either

40 THE SIX-FOOTED INSECTS

side a short distance from the margin of the compound eye,
and the third, if })resent, h)wer down on the face and on the
middle hne.

The lower ]jortion of the face is di^■ided into cli/peus,
which forms the basis for attachment of the lahrum or upper
lip, the moval)le flap-like part which covers the front part
of the mouth. Beneath this are the strong mandibles
capable of cutting and tearing the leaves of plants, and in
some cases of inflicting a severe bite if handled.

Next to these is a pair of more slender appendages, the
auxiliary jaws or the maxiUoe. These have a jointed structure
and bear each a slender, jointed appendage called the
tna.riUari/ palpus.

Beneath the maxillae is the labium, which is in reality a
structiu-e formed by the fusion of a pair of organs similar
to the maxilla^ and sometimes termed the second maxillae.
The first part of this organ is called the inenium, and is
attached by the submentum to the gula or basal part of the
head. Attached to the mentum are the glossa and 2^«^o-
glosscp, at the sides of which are the labial jMlpi.

The structure of the mouth is of special interest on account
of the relation to the food habits. It becomes possible to
determine from this structure what the food habits of any
particular insect may be. Where the mandibles and maxillse
are well (le\eloped and capable of biting and tearing the
foliage of plants, we may assume that the diet is herbivorous.
However, if the insect ca]:)tin'es and devours other insects
while the mandibles appear wanting or they seem to have
developed a suctorial tube fitted for puncturing the tissue
of plants and animals, a liquid diet may be assumed, and it
will follow that insects of this kind would not be affected
by poisons applied to the surface of the plants. We have
liere then a basis for the application of poisonous solutions
such as the arsenites, which are effective for those insects
which consume the surface of the leaf, or, on the other hand,
for the application of oil\- substances for those of suctorial
habits which enables them to secure the juices of plants
without consuming auA- of the siu-face. For insects of this

STRUCTURE OF INSECTS 41

latter type we must api)ly substances which penetrate the
body and close up the breathing jjores, and for this, oily sub-
stances, particularly kerosene, tobacco extract, and various
other substances, are especially useful. The breathing i)()res,
as will be seen later, are minute openings along the sides of
the body, these being closed by minute quantities of an
oily substance, so it is easy to see how these substances
operate to kill the insect.

The central region of the body, the thorax, consists of three
distinct segments called the pro-, meso- and metathorax.
The first of these next to the head bears the front pair of
legs; the middle segment, or mesothorax, the second i)air
of legs and the first pair of wings; and the hinder or meta-
thorax, the third pair of legs and the second pair of wings.
The legs are jointed appendages adapted for walking, run-
ning and jumping, sometimes for clinging, and consist of a
basal segment, the coxa; a large, strong segment, the femur;
a more slender segment, usually of the same length as the
femur, the tibia, and the terminal portion, composed of
from one to five small segments, called the tarsus. The
last segment of the tarsus usually bears a pair of strong
claws, and sometimes between these is located a disk-like
pad or brush called the pulvillus.

The wings, ordinarily four in number, are membranous
expansions of the body wall and are supported by stout,
thickened, and rod-like portions termed ner\'es or veins, and
the arrangement of these throughout the wings is spoken
of as neuration or venation. Wings are greatly modified in
different groups of insects. In some cases they are thin
and transparent in both pairs, as in the dragon fly. The
front pair may be thickened or leathery, as in the grass-
hoppers, or still more tliickened, forming a hard, horny case
(elytra), as in beetles, or ])artially leathery and partly mem-
branous, as in Hemiptera. They are broad and covered
with minute scales in butterflies and moths (Lepidoptera),
and the number is reduced to two in flies and mosquitoes,
the hinder pair being aborted or modified into special organs
called balancers or halteres.

42 THE SIX-FOOTED INSECTS

The abdomen or tliird region of the body is composed of
about nine or ten visible segments that do not bear any
segmented appendages, but the terminal segments are
modified to form the external reproductive organs. The first
seven or eight segments have on either side small openings
into the respiratory system, the spiracles, and there are also
usually two spiracles located on the thorax. They are so
small as to be scarcely visible without magnification. They
are connected internally with the delicate respiratory tubes,
the trachea, which extend throughout the body, so that the
air is distributed to all of the tissues and the respiratory
process is consequently carried on in all parts of the body.
The minuteness of the pores, as has been already mentioned,
makes it possible for the insect to be suffocated by a very
small amount of oily material spread over the pores, closing
them.

Some further details of structure will be given in connec-
tion with the general characters for each order.

The internal structure of insects may seem at first sight
to be of little relation to economic problems, but if it is
recognized that their modes of feeding and the character
of food depends upon the digestive organs, and their mode
of respiration is very directly connected with certain impor-
tant modes of treatment, and that all of their special senses
associated with the attraction to certain kinds of plants,
the attraction or repulsion to light or to odors, and in fact
that the activities of the insect, as a whole, are dependent
upon the organization, it can be realized that these structures
have a very direct relation to their injuries and to methods
of control.

The fligestive system of the insects is in general like that
of all arthropods, the mouth opening being connected with
a pharynx, the esophagus merging with the crop, commonly
the first part of the stomach (proventriculus), in which the
food is received and undergoes some digestive changes;
following this the true stomach around which are a number
of gastric ceca that secrete the gastric fluids. Following
the stomach is the intestine, divided into the ileum, colon,

STRUCTURE OF INSECTS 43

and rectum, and connected with tliis is the Malpighian
tubules which are excretory in function.

The circulatory system is simple; it consists of a delicate
tube near the dorsal wall, and in this the blood current is
carried forward and blood circulated freely through the
various tissues.

The respiratory system of insects is very different from that
of the vertebrates and in fact is of a type that occurs only
in part of the arthropods. It consists of a great number of
minute tubes, tracheae, which are distributed throughout the
tissues, so that the air contained in the tubes may be
brought in contact with tissues in all parts of the body.
Externally these tracheae open through the spiracles which
have been noted as located on the thorax and abdomen.
The tracheae arising from the abdominal spiracles in most
insects unite each side with a longitudinal tube running
through the abdomen into the thorax, and from this lon-
gitudinal one numerous smaller tracheae are given out, and
these in turn divide into smaller branches until they ter-
minate in minute parts called tracheoles, which are so deli-
cate that the air contained in the tubes is readily absorbed
into the surrounding tissues. The movements of respira-
tion are fairly rhythmetical in expansions and contractions
of the body, expecially of the abdomen, serving to force
the air in and out of the spiracles. Minute valves in the
spiracular openings permit air to enter and closely hold the
contained air, so that further contraction of the muscles
serves to force the new supply of air out into the minute
tracheoles. It is very evident from the structure of the
respiratory system that contact insecticides which serve
to close the spiracles or which may penetrate along the
trachea and be absorbed into the tissues must serve very
effectively for the destruction of the insect. It is for this
reason that contact poisons, and especially oily substances,
such as kerosene emulsion, are so efficient in the control of
suctorial insects.

The nervous system of the insect consists of a ladder-like
arrangement of ganglia and fibers along the ventral wall

44 THE SIX-FOOTED INSECTS

of the body, se])arating at the anterior end, so as to pass
around the esophagus, after which there is a large mass,
frequently termed the cerebrum, as it occupies the upper
part of the head. This gangUonic mass contains three
pairs of gangHa, while the subesophageal is composed of
three or four, and the primitive distribution of thorax and
abdomen is one pair of ganglia to each segment. This con-
dition is modified, especially in the higher insects, so that
the ganglia may be fused, causing a single ganglion in the
thorax, and five, three, or one in the abdomen.

The various ganglia of this system act with considerable
independence and even dismembered parts of an insect may
maintain their movements if the ganglia are not destroyed.

The special senses present many diverse features as com-
pared with higher animals, but insects give good evidence
of possessing sight, hearing, smell, taste, and touch, although
the exact range of these functions may differ considerably
from the same senses of vertebrates.

The reproduction in insects agrees for the most part with
that of other arthropods, and except for certain remarkable
dcN'iations, such as are found on the aphids and bees, a
general statement will suffice. Insects have separate sexes,
and in a great majority of cases the males' and females are
distinct and usually may easily be distinguished by external
characters. The reproductive organs are located in the
abdomen, the ovaries in the central anterior part, and are
composed of a number of ovarioles or tubular structures,
within which the ova are developed and from M'hich they
pass into the oviducts. These oviducts combine near the
end of the abdomen into a common duct leading to the
external opening. Frequently connected with this common
duct is a sac-like structure, the spermatheca, which serves
for the retention of the spermatozoa. In the males the testes
are located about as the ovaries, and lead by rather slender,
more or less curved vasa deferentia to a common duct which
leads to the external opening at the posterior end of the
abdomen. The external organs are modified widely in
different groups of insects, and in many cases furnish most

THE TRANSFORMATION OF INSECTS 45

important characters for classification. In general they
consist, for the female, of the ovipositor, and in the male, of
external claspers and a central intromittent organ.

Mating, in mkny insects, is accomplished during flight,
but this is by no means general.

The eggs are fertilized in the oviduct, in most cases doubt-
less in the common duct, or in the vicinity of the sperma-
theca, and the spermatozoa enter the egg by way of a minute
pore termed the micropyle, located usually at one end of the
egg.

THE TRANSFORMATION OF INSECTS.

Insects, like all other animals, begin their develojiment
from an egg, not unlike any other forms. They pass through
a series of more or less distinct stages in development from
the egg to the mature or adult form. These stages are desig-
nated for the insects in general as egg, larva, pupa, and
imago. While differing greatly in the definiteness of separa-
tion between the different stages, it is convenient to use
these terms in tracing the life history of any insect and in
describing the character of each of the stages somewhat
more in detail and considering the bearing in the connection
with economic treatment.

The egg is generally a c()m])aratively small object, con-
taining a considerable portion of yolk material and i)rovid-
ing for some degree of development before hatching. The
shapes differ greatly in the different forms, perhaps the
most common, and consequently the most fundamental,
being an elongate, oval shape. Spherical forms are by no
means scarce, and flattened spherical, elongated spherical,
or even linear or cylindrical forms are very common. The
greater difference may be noted in the character of the
surface of the eggshell, which may be minutely reticulated,
striated, punctin*ed, beset with fine spines, and frequently
having a distinct lid through which the larvae are to
escape. They may be placed loosely in suitable locations,
attached simply by a glutinous secretion, forced into the
tissue by the ovipositor, etc. For aquatic species they may

46 THE SIX-FOOTED INSECTS

be arranged in clusters on the surface, attached to objects
above the surface, to leaves overhanging the water, to stems
of aquatic plants, either above or below the water line, and
for some of the distinctly aquatic forms placed upon the
bodies of the insects themselves. The period of incubation
varies enormously, some hatching immediately upon deposi-
tion, or, in some cases, preceding deposition, in which
case the insect appears to be viviparous and for the other
extreme remaining in the egg stage for many months, many
species passing the winter in this stage. Ordinarily the
eggs of any particular egg mass, or of any species, hatch
with great uniformity, so that larvse will appear at the
same time. This results at times in the very sudden appear-
ance of larvae in startling numbers and to the iminitiated
suggests the occurrence of some very remarkable invasion.
Usually no nutritive material, other than contents of the
egg, can be used during this period, but some species in
which the eggs are forced into plant tissues and in which
the egg covering must be very delicate, there is an absorp-
tion of fluids indicated by the distinct increase of the size
of the egg prior to hatching The hatching of the egg is
usually accomplished simply by pushing off of the egg-cap
or rupture of the egg membrane, but in some species it
depends upon external factors associated with the future
history of the larva. For instance, the eggs of the horse
bot fly are hatched only upon the application of friction
or moisture and warmth, conditions which are brought
about when the horse licks the hair bearing the eggs and
thus provides ready means of transfer from the eggshell
to its mouth, thus providing the necessary conditions for
future development of the insect. The particular method
of hatching may therefore have very important relation
to preventive or remedial measures.

The larval stage is the active feefling stage during which
the growth of the insect occurs, and during this period there
are a varying number of moults, most frequently from four
to five, at which there is a rapid increase in size, the larva
accommodating itself to the tough, chitinous body wall,
which as soon as hardened is incapable of any expansion.

THE LENGTH OF THE LARVAL PERIOD 47

The larvse present the most diverse characteristics for the
different groups of insects, and vary extremely even for
closely related species. There has been a distinct adapta-
tion to conditions during this stage, and larvae with slightly
varying habits have doubtless been affected by natural
selection in the same manner as adults have been affected
by their particular environment.

THE LENGTH OF THE LARVAL PERIOD.

The length of the larval period is also in a wide degree
an adaptation of this kind, which is frequently of the utmost
importance in economic treatment of the species.

The pupa stage is the connecting stage between the larva
and the adult, and may be similar to larval form or differ
markedly from it, according as the insect has incomplete
or complete metamorphosis. While in some forms it may
feed to some extent, the more common condition is that of a
quiescent non-feeding period. During this stage, however,
important internal changes occur which lead to the maturing
of the insect. For those forms which have a perfectly
quiescent pupa stage, various forms of cells are made within
which the pupation occurs, others secrete themselves in
rubbish, folds of leaves, crevices or cracks in bark, while
some construct a tough, silken cocoon as a permanent
protecting case.

The adult stage or imago differs usually from the preced-
ing stage in the acquisition of well-developed wings, except-
ing, of course, in the wingless forms, and especially in the
maturity of the organs of reproduction. The period of
life varies in the adult also in quite a degree for species
living over winter and others for varying periods, although
more commonly the adult perishes soon after the comple-
tion of the reproductory process. To indicate the various
forms of adults would be to review all the different groups
of insects, and hence need not be attempted even in brief.

A very distinct grouping of insects may be made with
reference to the definiteness of transformation. Those
which develop without marked changes between the different

48 THE SIX-FOOTED INSECTS

stages are said to \\a.\e incomplete metamorphosis (hetero-
metabolic). Those which have very striking or marked
differences between these stages, inchiding the distinctly
quiescent, non-feeding pupa stage, are said to have complete
metamorphosis (holometabolic). A third group is sometimes
noted for the primitive forms in which no change whatever
occurs, and in which no wings have developed, they being
said to be without metamorphosis (ametabolic).

A reference to some of the common injurious species,
in which the different stages are shown, will illustrate these
different phases of develo])ment.

CLASSIFICATION OF INSECTS.

At this point it is well to discuss in a brief way what is
termed the classification of insects. When we speak of
the different members of the animal kingdom or describe
some particular insect it is quite important that we have
and use a name which would be distinctive for that one
form. The general practice is to use two names for each
insect, namely, the genus name and the species name.
A species includes those which are similar in habits and
characteristics and that may interbreed as a species or a
kind. A genus includes a number of species and a group of
genera with more general similarities form a family, and
families are grouped into orders. The order then is the
more general group and the class insecta includes about
twenty orders.

Apterygota (Primitive Wingless Insects).

Order 1. Thi/saitura, Bristle tails; Campodea, Lepisma.
Order 2. (\)UcinhoJa, Spring tails; Podura, Smynthurus.

Pterygota (Winged Insects).
With Inconiphie Metamorphosis.

Order 3. Orthoptera; Cockroach, locust, cricket, mole
cricket, "walking stick," "walking leaf." Biting mouth

CLASSIFICATION OF INSECTS 49

parts. Anterior wings usually shorter and firmer than those
behind, or modified into wing covers. Both pairs are some-
times absent.

Order 4. Dermaptcra; Earwigs. Biting mouth parts.
Anterior wings small; hind wings large, but folded both
longitudinally and crosswise. Posterior forceps.

Order 5. Plecoptera; Perla. Biting mouth parts. Two
pairs of wings or none. Larvae aquatic.

Order 6. Ephemerida; May flies. Adult mouth parts
degenerate and rarely used. Fore wings large, hind wings
small or absent. Larvse aquatic, with biting mouth parts.

Order 7. Odonata; Dragon flies. Biting mouth parts.
Two pairs of large unfolded wings. Larvae aquatic.

Order 8. Isoptera; Termites. Biting mouth parts.
Wings often wanting. Social in habit.

Order 9. Corrodentia; Book lice. Psocids. Biting mouth
parts, wings often wanting.

Order 10. Mallophaga; Bird lice. Parasitic, wingless,
with biting mouth parts.

Order 11. Thysanoptera; Thrips. Suctorial mouth parts.
Wings very narrow, often rudimentary or absent. Only
three or four pairs of stigmata. Concentrated nervous
system.

Order 12. Hemiptem; Phylloxera, aphides, scale insects,
cicadas, bugs, water scorpions, lice. (Male scale insects
(coccidae) have complete metamorphosis.) Mouth parts
adapted for sucking and piercing. Two pairs of wings or
none. No compound eyes iu parasitic forms which are
degenerate in several respects.

With Complete Metantorphosls.

(Holometabola.)

Biting Mouth Parts (Mandibulate).

Order 13. Neuroptem; Ant lions, lace-winged flies. Two
pairs of glassy wings with many nervures. Larvie sometimes
aquatic.

50 ■ THE SIX-FOOTED INSECTS

Order 14. Mecoptera; Scorpion flies. Two pairs of narrow,
membranous wings or none. Larvae caterpillar-like.

Order 15. Trichoptem; Caddis flies. Hind wings usually
larger than fore wdngs, both folded like fans. The body is
hairy, rarely scaly. The larvae are somewhat caterpillar-
like, usually live in the water in special cases, and are
apneustic.

Order 16. Coleopiera; Beetles. Fore wings modified into
wing covers, hind wings folded when not in use. Larvae
very diverse, generally with feet. The little bee parasites
Strepsiptera are probably allied.

Suctorial Mouth Parts (Haustellate).

Order 17. Diptera; Two-winged flies. Mosquito, midge,
gnat, gad fly, house fly. Sucking mouth parts, but some-
times with power of biting. Two anterior transparent,
unfolded wings and posterior "balancers" or "halteres."
Lar^•a usually a footless maggot, without a distinct head.

Order 18. Siphonaptera or Aphaniptcra; Fleas. Wingless.
No compound eyes. Ectoparasitic. Larva a footless
maggot.

Order 19. Lepidoptcra: Butterflies, moths. Two pairs
of uniform, scaly wings. Larva, caterpillar.

Mouth Parts Developed j or Biting and Sucking.

Order 20. Hymenoptera; Ants, bees, wasps, gall flies,
saw flies, etc. Usually with four transparent wings. Lar\se
are footless grubs, except in saw flies.

chaptp:r IV.

LOWER PTERYGOTA.

{Wituilc.s.s In.sects — Bristle Tails and Spring Tails.)

This group of insects includes those forms which are
primitively wingless, there being no trace of wing structure,

Fig. is. — Lepisma doincstica: Adult female — enlarged. (After
Marlatt, Div. Ent., U. S. Dept. Ag.)

(51)

52 LOWER PTERYGOTA

and the evidence showing conchisively that unhke certain
wingless forms, which are related to winged species, these
have not had any winged ancestry. These species are
minnte, scaly, mouth parts fitted for biting. The develop-
ment is direct, the young hatching in the form of the adults
and developing by simple growth to the adult stage.

¥10. 19. — Lepisnia saccharina: Adult — enlarged. (After Marlatt,
Div. Ent., U. S. Dept. Ag.)

Order THYSANURA.

This group, the "bristle tails," includes the forms which
are provided with three bristles or bristle-like appendages
at the posterior end of the body. The antennae are long.

ORDER THYSANURA

53

slender, bristle-like, the Ixxly usually densely covered with
overlapping scales.

Fig. 20. — Lepidocyrtus purpureus (Lubbock): 1, dorsal view of insect;
2, spring; 3, side view of dens showing serrations and barbed hairs; 4,
foot; 5, side view of mucro; 6, larval form; 7, eyespot of larval form
(From Ohio Naturalist. After Mrs. Alma D. Jackson.)

The common bristle tail of dwellings, Lepisma doinestica,
is about one-half inch long, of a light silvery color, with
some darker bands on the back. They run ' with great
rapidity and are very smooth and flexible, so that they are

54 LOWER PTERYCOTA

caught with difficulty. If caught tlie scaly covering brushes
oft' readily as a fine, whitish dust.

A related species, Lepisma saccharina, is found, especially
in pantries, bakeries, or in places wdiere they can secure
starchy materials for food. In some cases they attack the
bindings of books or the starchy covering of la})els, and may
cause a good deal of annoyance and injury- in libraries.

Order COLLEMBOLA.

This order, including the spring tails, is characterized
at once by the strong spring which is folded under the
abdomen and which catches into a loop on the thorax. The
release of the spring from this throws the insect into the
air with a sudden spring, which doubtless serves it as a
protection against certain kinds of enemies. The species
are generally found in moist places in cellars, under loose
boards, chii)s, or stones, and some of them are found ftoating
on the surface of water in quiet pools or along the margins
of streams or ponds. They feed mainly on decaying organic
matter and are of little economic concern, but a few species
are credited with feeding on vegetation, especially in green-
houses.

THE LOWER WINGED INSECTS (PTERYGOTA).

The remaining groups are primarily winged, and a numl)er
of the lower orders may be grouped together in this chapter.

Order ORTHOPTERA.

This order, including cockroaches, crickets, grasshoppers,
etc., is distinguished by the biting mouth parts being rather
simple and ])rimiti\e in structure, the wings of rather simple
pattern, the front wings narrow and the hind wings broad
and folded in a fan-like manner, so as to be coverefl by the
fore wings when at rest.

They differ in their mode of locomotion, some having
rapid running movement, using all of the legs equally well,
others walking slowly, and others, more specialized, having

ORDER ORTHOPTERA 55

the hind legs much enlarged and adapted for leaping. The
group is conveniently divided on the basis of their move-
ments into the rinniing or walking and the jumping divisions.
Cockroaches. — Of these groups the cockroaches, family
BJaiiukr, may he considered as about the most ])rimiti\e
representatives for the winged insects, the P>phemeri(Ue,
often placed as the lowest order, having been specialized
in the direction of aquatic life. This position is supj^orted
by the primitive structiu-e of the mouth, by the venation of
the wings, and also by the fact that they are to be found in
strata of the early Paleozoic era, the earliest to appear of the
winged insects whose structure agrees quite closely with
that of present-day cockroaches. No other winged insects

Fig. 21. — Ischnoptera fietm.sylvanica. After Lugger

have been found in any numbers in as early geologic forma-
tions. Cockroaches of the present t'me seem to be persistent
forms that have preserved ancestral characters. Their
life history is interesting on this account.

One species of cockroach {Ischnoptera pennsyJminca) is
fairly common in woods under bark of dead timber and
sometimes in houses. The females are often found with the
egg-capsules protruding from the body. It is abundant
all over the I'nited States and is really an outdoor native
species. They ha\e well-developed wings, and often fly
into houses and are found in stumps, under logs, etc., during
daytime, and make migrations during the night, or in the

56

LOWER PTERYGOTA

evening and early morning;-. They are seldom active during
the bright part of the day. The egg-capsules are bean-shaped
and contain 50 to 60 or more eggs packed closely together,
and after being carried some time are probably slowly
extruded, finally left in some crevice. The young hatch
from the egg-capsules and for a time are somewhat gregarious
and are inclined to cluster together in company with the
adult. This ma}' be simply an incident of location, though

Fig. 22. — The oriental roach (Periplaneta orienfalis): a, female; h,
male; c, side view of female; d, half-grown specimen — all natural size.
(From Marlatt, Div. Ent., U. S. Dept. Ag.)

it appears like maternal care. The young are similar to the
adults in shape, much flattened, and much lighter in color,
and the wing pads are scarcely visible. They grow by
successive moults, and with each moult the wing pads
increase in size, until in the final moult they acquire the full-
sized wings of adults. The development of the nymphs
goes on somewhat irregularly during the summer months.
An introduced species, the Oriental cockroach {Periplanda

ORDER ORTHOPTERA 57

orientalis), is a common species in houses and is responsible
for much annoyance in kitchens and pantries. Another
introduced species, the German cockroach {Ectohia ger-
manica), is much smaller, but a persistent pest in houses
and common in eating houses, bakeries, and other places
where starchy food is available.

The second family in the group, Mantidop, Praying Man-
tides, have the front legs much modified for capturing insects.
These legs have a peculiar structure. Instead of having
short coxse with elongated tibia, the coxa; are very much
elongated. This is evidently correlated with the grasping

Fig. 23. — Praying mantis. (After Lugger.)

habit, and is paralleled in Emesidfe and Nepidae. They are
rather tropical in distribution, occurring in the Southern
States.

One species, Pha,s'momantis Carolina, is found to some
extent in southern Ohio and north to Washington, D. C,
but is rarely taken in the northern part of the I'nited States,
or, in general, north of 40 degrees of latitude. The pairing
habits of the adults are rather interesting. The females
often capture and devour the males during the process of
courtship. The eggs are laid in large masses attached to a
twig or some part of a plant, grouped together, lying one

58 LOWER PTERYCOTA

over the other in a dense mass and exposed freely and rather
commonly attacked by parasites.

Fig. 24. — Diapheromera femorata. (After Lugger.)

Family Phasmidse. — The Walking-stick (Diapheromera
femorata). — The walking-stick is a conniion representative of
this famil\- throughont this ])art of the country. It has a

ORDER ORTHOPTERA 59

slender body and reduction of wings. The female is green
and the body is thicker than that of the male. In autumn
the bodies of the males become brown and resemble in color
the twigs on which they are found. This species has one
generation each year, hatching about the first of June,
and the adults maturing in the latter part of the summer.
The adults are found as early as the first of September.
They are most commonly found in trees and shrubbery,
at some little distance from the ground. Eggs are simply
dropped from the trees or shrubs on which the adults are
resting, and instances are cited where they are so abundant
that the dropping of their eggs makes a sound like the
falling of rain. The eggs rest on the ground and are pro-
tected more or less completely by leaves. They retain
their vitality through winter and early spring and hatch
in early summer. This represents a rather simple life-cycle
with an annual generation and one in which the winter is
l)assed in the egg stage. When these insects are so abundant
as to be injurious, it would be of service to rake up and
burn leaves, but they are not usually abundant enough to
do any great damage. Another way would be to spray the
trees with arsenical poison at the time the young are feeding.
They are leaf-feeding forms and would secure the poison
with their food. A grass-feeding species, Monomcra blatrh-
ley, occurs in the jNIississippi Valley.

Some of the tropical forms are more striking than this
native variety and show more forms of mimicry. One form
has wings in form and ^•enation like the lea^'es of certain
l)lants, so that the insect is remarkably well protected.
Other forms simulate growths of lichens, etc. The whole
family seems built on the plan of representing protecti^'e
resemblances. Several species have the same form as the
walking-stick, but possess short wings. There is a wide
divergence in wing development.

The Locusts { Acrid idcp). — The locusts include some of the
most important economic species. They are great pests in
some ])arts of the country. The group includes the old-world
migratory locusts, which still ai)pear as an occasional ])lague

60 LOWER PTERYGOTA

over some parts of northern Africa. The old-world species
is represented in this country most nearly by the western
migratory locust or the grasshopper of the western plains,
Melanoplus spretus. This western species, the devastating
locust, is far less destructive in the aggregate than one or
two other species, but has attracted more attention because
of complete devastation which follows its appearance.
There is one species in Argentina that has attracted a great
deal of attention and has been a great menace to the crops
of that country.

The Devastating Locust. — The devastating or Rocky
Mountain locust, is limited in its normal distribution to the
plateau region of the Rockies, the normal conditions for its
survival being the high altitude, dry atmosphere, and a
supply of grassy vegetation. They are most dependent on
the buffalo grass or other native grasses. The species became
important during the days of early settlement of that portion
of country just east of the mountains, because at times,
when vegetation ran short in its native breeding ground, it
migrated sometimes 300, 400 or 500 miles, reaching places
that were settled and proving extremely destructive to
growing crops. During the late 70's they were such a serious
source of injury that a very decisive effort was made to
work out their habits, life history, and means of suppression.
It is now generally assumed that it is only under conditions
when it becomes extremely abundant and must migrate that
it causes serious devastation outside of its regular breeding
ground.

The adults may fly long distances and after finding suit-
ble places for depositing eggs, bore into the ground with
the ovipositor and abdomen for one and a half or two inches.
The process consists of merely pressing the earth away by
the ovipositor, and denotes a great degree of power because
the eggs are preferably deposited in hard ground where
the soil is packed. The eggs are coated with a glutinous
secretion which protects them from the weather and they
remain in these little burrows through autumn and winter
and liatch early in spring. Sometimes they hatch before

ORDER ORTIIOl'TERA

61

there is much vegetation and sometimes the young are killed
off in large numbers by late frosts. The young develop
pretty rapidly and are able to travel quite considerable
distances, especially if vegetation is scarce. They acquire

-Mduuoplus fcmur-ruhrum, female. (After Lugger.)

wings often as early as the latter part of Jime. Flights may
occur as early as July and often in August and September.
Migration probably occurs rather sparingly unless food
supply is scanty.

62 LOWER PTERYGOTA

We have several species in the eastern United States closel\'
rehited to the Rocky IMountain species. The most common

Fig. 2(S.—Mdnnoplus allunis, male. (After LuK^f^r.)

Fig. 27. — Melanoplus atlanis, female. (After Lugger.)

is the red-legged grasshopper {Mehnioplus femur-rubrtnn).
It is similar to the Rocky IMountain species, but is not cap-

ORDER ORTIIOPTERA

().']

able of any sustained fli<i;ht. There is seldom anythinji like
a general migration. They will travel out of dry pastures
into corn, wheat and oat fields, and sometimes injure apple
trees. Their ordinary hal)itat is in pasture or meadow and
grass is their most common food. This species is abundant
all over the eastern Ignited States; is an economic factor

Fig. 2S. — The yellow-winged locaist (Canuiula pell ucida) : a, adult male;
b, female: c, nymph — somewhat enlarged. (After Simpson, Div. Ent., U.
S. Dcpt. Ag.)

year after year, and iuidoul)tcdl\- causes more damage than
the Rocky Mountain species. They do not usually destroy
the grass completely, but take a large share of the crop.
If they were eliminated the same acreage would supply
more hay, or support more cattle or other stock in pastiu'c.
Plowing the ground where eggs have been (iei)osited, rota-

64

LOWER PTERYGOTA

tion of crops, and the catching of the newly hatched hoppers
in early summer before the damage has been done are
measures that will assist in keeping them in check. They
are preyed upon by several parasitic and predaceous insects

\ /

Fig. 29. — Trimerotropis maritima, female. (After Lugger.)

and by spiders and birds as well as fungous diseases, which
together serve to hold their numbers down.

Another very similar species, but with longer wings, and
which occasionally has a migration, but probably not so

ORDER ORTHOPTERA 65

uniformly destructive, is Melannplus atlanis. The wings
are long and the capacity for flight more like Melannplvs
spretus, but flight seldom reaches more than a few miles.

The Beach Locust {Trimerotrojjis maritima). — The beach
locust is an interesting species that occurs along the coast
of the ocean as well as fresh-water lakes or where sand dunes
are common. The coloration and markings are very dis-
tinctly adapted for protection and the nymphs are really
about as well protected as the adults. They are conspicuous
on the wing, part of the wing being bright yellow in color,
but when they alight on the sand they immediately disap-
pear on account of the color and markings. They must
feed on grasses in such locations and are often found around
clumps of Juncus and Arenaria, but rarely seen feeding.

Fig. 30. — Tritnerotropis maritima, male. (After Lugger.)

This species is found in June and July in the larval and
nymphal stages, and in different sizes, some comparatively
small, representing the second and third moult. Their
moults occur fairly rapidly during this particular time.
There is some difterence in the time of hatching from eggs,
and adults are to be found by the early part of July. The
time varies in different seasons. Later in summer there will
be very few larvse and a large number of adults, and still
later only adults. The adults remain active and travel
over the sand for several weeks. They make characteristic
tracks on the sand, easily detected. They probably do not
5

00 LOWER PTERYGOTA

mate until somewhat late in the season, seldom during mid-
summer, but probably by the latter part of August.

In regard to the deposition of eggs, it would seem that
they must select rather solid parts of the sand, but egg
masses have not been found. There is no way for the
nymphs to travel any great distance. The eggs must be
deposited during the autumn months, ])rol)ably in September
and October. They survive the winter protected in the

Fig. 31. — Dissosieira Carolina, female. (After Lugger.)

sand or in places where there is more solidity in the soil.
The eggs hatch in the spring, probably in June, some perhaps
in May. It does not seem necessary for them to adjust
themselves particularly at this stage to any conditions, for
the life-cycle can be carried through easily in summer.
There is one generation a year.

The more common form is a rather light gray, with the
spots of a rusty color, and some spots of darker color, a granite
combination, resembling the surface of the sand. Another

ORDER ORTHOPTERA

07

fairly common form has a brownish band or stripe on the
upper part of the thorax or wing covers, and making a promi-
nent hne when tlie wings are closed. It occurs about as
commonly on the sand, but may have a preference for places
where there are little sticks. A less common form is lighter
colored, almost ochre yellow, and more common among
grass, leaves, and clumps. The color is close enough to the
general color of the sand to afford some protection on the
bare sand.

Arphiu md/jhurca. (After Lugger.)

Family Locustidae. — The family Locustidfie includes insects
which are usually green in color and called green grasshoppers
or meadow grasshoppers, katydids, and stone crickets.
They are characterized by great length of antenna^, the widtli
of wings, and generally a green color. They are common
among the coarse grasses along the roadsides and in
meadows. A rather striking group includes the sword-
bearers, Conocephahis, the striking feature being the form of
the head, which is extended in a prominent horn, \arying
somewhat in size and shape in different species and with
long, slender antennae. The wing covers are somewhat

68 LOWER PTERYGOTA

sword-shaped and the ovipositors also have a sword-like
shape. They are found during the latter part of the summer
as adults, occurring on grasses and low vegetation, but
seldom on shrubby plants or trees. The females use the
long, sword-shaped ovipositor for thrusting eggs into the
tissues of plants, and thus they are protected during the
winter time. The eggs hatch in the spring and larval devel-
opment occurs during the early summer, the adults appearing
in the middle or latter part of summer.

Katydids. — The katydids include several species, but
the one most properly called katydid has broad, concave
wings with rather prominent veins, quite strongly concave.

Fig. 33. — Conocephalus enniger, female — natural size. (After Lugger.)

The name of the species is Cyrtoyhylluvi concavum. They are
noted for their song, and sing particularly during the twilight
and early part of the night. This species is the best singer
of the katydids. Their life history is practically the same
as that of Conocephalus.

A species nearly related to this is the angular-winged
katydid, which deposits eggs on the surface of twigs, the
eggs overlapping each other like tiles on a roof.

Stone Crickets. — In this family also have been placed the
stone crickets. Most of them are included in the genus
Ceuthophilus. Quite a large number of species is included
in this genus. They have changed from the food habit of

ORDER ORTHOPTERA 59

the other members of the group, and instead of feeding upon
ordinary vegetation they secrete themselves in dark places
and feed upon debris or decaying organic matter occurring
in such i)laces. The character of the ovipositor is like that
of the crickets, but the head, antennae, and other parts
look like those of field locusts. The details of their life his-
tory are not fully worked out, but it is probable that there
is one generation a year.

Family Gryllidae. — This family includes the crickets and
may be separated into herbivorous, carnivorous, and omniv-
orous forms.

Oeccmthus, tree crickets. Oecanthus niveus, snowy tree
cricket, is most commonly referred to, but 0. fasciatus and
other species are more common. The larva? feed upon plant
lice and are distinctively carnivorous, and therefore are
serviceable during that stage. The adults may feed on flies,
but were formerly thought to be herbivorous. The adults
are found in autumn, and then they gather on various kinds
of trees, fruit trees, etc. The eggs are forced into the twigs,
forming a series of punctures. The eggs are deposited in
two rows. They are elongated in form, and the masses of
eggs include forty or fifty eggs depositerl by each individual.
The eggs remain in the twigs during the winter and are well
protected in that way. They are sometimes deposited in
galls on willows; if not by this species by one closely related.
Some eggs are forced into the stems of annual plants, Helian-
thus, Solidago, etc. The eggs hatch during the spring sea-
son and the larvse depend upon plant lice for food supply.
They grow to reach adult stage, when they probably feed
upon other insects. They are probably not destructive, and
the attacks upon plant lice make them valuable. .They are
rather desirable on fruit trees, only in some cases the punc-
tures of the twigs result in rather severe pruning.

A quite common species on Helianthus is Oecanthus fas-
ciatus. There are four or five species that look a great deal
like the common forms. In the males the wings are broader
and very transparent. One form lays eggs in separate punc-
tures at different points.

70

LOWER PTERYGOTA

The mole crickets are extremely specialized as subter-
ranean forms. Tliey burrow in the earth and have become
adapted to this habit. They have a dense velvety covering,
which is doubtless serviceable as a protection against mois-
ture, etc. In one species the wings are considerably reduced,
but in another species they are longer. In all the species
the legs are well developed, and are excellent for digging and
burrowing, with toothed arrangements for pushing into the
soil, much as in the mole and other digging animals. These
teeth are mostly on the tibia. The tarsi are rather slender.
Almost the same kind of structures occur in certain beetles

Fig. 34. — Grylloialpa Columbia: a, side view of anterior claw; b, the
same of G. horealis. (After Lugger.)

and in burrowing Hemiptera. The mole crickets feed on
vegetation, especially tuberous roots of plants; sometimes
they dig into potatoes. Ordinarily they are not abundant
enough to attract much attention. The long-winged form
flies at night and sometimes flies into houses. They are
completely covered with a fine pile, as velvety as that of a
mole, and are also as well fitted for burrowing.

EUPLEXOPTERA (DERMAPTERA).

Earwigs. — The earwigs, or Euple.voptcru, are characterized
by the presence of four wings, the first pair of which are very

EUPLEXOPTERA

71

short, veinless, and meeting in a straight hne when at rest,
the second pair of which fold both lengthwise and crosswise;
biting mouth parts; forceps-like caudal appendages; incom-
plete metamorphosis.

Fig. 35. — Labia minor. (After Luggor.)

These forms resemble ro\'e l)eetles in appearance, being
very long and slender, but difi'er in having the caudal appen-
dages. They are found in the southern part of the United
States and on the Pacific Coast, and are very common in
parts of Europe, where they are troublesome, because of
their habit of feeding on flowers and fruits.

72 LOWER PTERYGOTA

A common species in the northern states is Labia minor,
which occasionally may be seen flying in large numbers
around barnyards. It has not occasioned noticeable injury,
however, and is not counted of special economic importance.

Order PLECOPTERA.

This grou]) includes the stone flies, and the species are
all aquatic, but in general characters they are pretty closely
related to the Orthoptera. The mouth jjarts are mandibu-
late, the front wings are narrower than the hind wings, which
fold together and are co\ered by the front wings when at
rest. The transformations are incomplete, the larvse dis-
tinctly aquatic and provided with tracheal gills along the
side of the body, which permit them to absorb oxygen from
the water. The species have an importance as a source of
food supply for aquatic animals, and in some localities they
probably furnish a considerable support for certain kinds of
fishes.

The adults are usually found in the vicinity of water, on
tree trunks or rocks, but except as they may attract atten-
tion they have no particular importance. Unlike the May
flies, they are not strongly attracted to light, and are seldom
noticed except in their native habitat.

Order EPHEMERIDA.

May flies form an order frequently placed as the lowest
of the winged insects. While showing some simple structure,
we may consider their simplicity due to reduction or speciali-
zation. The mouth parts of adults are reduced, fore wings
large, hind wings small. They are specialized in the aquatic
habit of the larval stage. The genera and species are not
particularly numerous. The name Ephemera was applied
on account of their very short apparent life. They are
developed from aquatic forms that have a period of develop-
ment of from one to three years, but have a very short life
in the adult stage. There are many species that come out

ORDER EPIIEMERIDA 73

toward evening and fly for an hour or two, deposit their
eggs, and then disappear. Other species Kve for several
days, some perhaps for a week or two. Their first flight
is in what is cafled the pseudimago stage. When coming
to rest they attach themselves to some convenient object,
and there the skin of this stage splits and the insect escapes,
leaving the skin still clinging to the object. After this
moult they are mature adults with full-sized wings, but with
a difference in texture, and in genital organs, which are not
fully developed in the pseudimago stage. For many of the
species it is probably safe to say that they mate the same
day that they come out of the pseudimago stage. The
normal method of mating is on the wing. Eggs are probably
deposited within a day or two, being laid either on the
surface of the water or else underneath the surface. This is
done by the adult folding the wings and descending beneath
the surface. In one species the eggs are extruded in long
packets and then the insect descends close to the water and
deposits them on the surface.

The eggs after deposition in one way or another — in or
on the water — hatch in a short time and the larvse grow and
probably migrate more or less in the water. They do not
have to come to the top of the water for respiration, as they
are fitted with organs which provide for aquatic respiration,
and probably live two or three years in the water. The
adults appear every year, and if the larvse require two or
three years to grow, there must be different broods, and if
there are two or three different generations in the lake, there
must be an enormous shifting of its population. They con-
stitute an enormous body of animal life, furnishing the basis
of food supply for other forms of animal life, fishes, etc.,
which in a few days shifts its position and disappears, thereby
lessening the food supply materially. The larva; of these
nymphs come to the surface and the skin splits and the
pseudimago form issues and flies. The exuvise or skins which
are left on the surface drift in on shore and pile up in wind-
rows on the beach.

74 LOWER PTERYGOTA

Order ODONATA.

This group includes the dragon flies and (himsel flies,
insects with incomplete metamorphosis, biting mouth parts,
and large, net-veined wings without folds.

The larv{3e of these dragon flies and damsel flies are aquatic
and distinctly predaceous, feeding on aquatic animals.
The adults are also predaceous and catch insects in flight
very readily. The former, particularly, have very swift,
rapid flight, and may be seen darting here and there, espe-
cially in the vicinity of water, while the latter fly somewhat
more slowly. Both groups catch insects and feed upon
them, and so they are thought of as being beneficial, since
many of the insects that they feed upon are destructive.

The eggs in all cases are laid close to the water's edge,
either at or jusc above the surface, or in some cases attached
to stems of water plants beneath the surface. When the
larvae hatch they are already under water and can begin
their active life, preying upon the aquatic animals. In
both adult and larval stages the mouth parts are provided
with strong mandibles fitted especially for biting. In the
larval or nymphal stage there is a very peculiar enlargement
and elongation of the labium, so that it becomes a large
mask for the front part of the head, covering the outer
mouth parts and lower part of the face. These are provided
with a pair of very strong, clasping, or pincer-like organs,
which are used in capturing the aquatic animals on which
they prey. The elongated and jointed structure of the
labium permits the insects to thrust this forward a distance
of about half an inch from the head, so that they can reach
out and capture animals that seem to be out of their reach.
These are snatched up very quickly and ground up with
their mandibles.

After passing the larval stage they crawl out of the water
on the bank of the stream or pond or sometimes on the stem
of a plant, then the nymphal case splits along the centre
line of the back, the adults draw themselves out of this

ORDER DON ATA 75

case, their wings expanding rather slowly or gradually. In
about a half-hour they are ready for flight.

Their very rapid movements and habits have given rise
to a number of common names. Aside from the dragon
fly they are called mosquito-hawks, which is quite appro-
priate on account of their feeding on mosquitoes. Sometimes
they are called snake feeders or snake doctors. In the
past the name devil's darning needle was quite popular,
although not used much at present. It was said that they
sewed up the ears of untruthful children.

Fig. 36. — Dragon fly Libellula pukhella. (Photo by author.)

These different common names illustrate different popular
interest in the group and forms of superstition. These
insects seemed to inspire a great deal of dread before their
life history and habits were known definitely.

The group Odonata can be looked upon as being very
useful and serviceable to mankind, as they feed on destruc-
tive insects, mainly mosquitoes and many aquatic organisms.
Of course they feed on useful insects as well as detrimental
ones, but it is generally believed that the majority are detri-
mental ones.

76

LOWER PTERYGOTA

Throughout a large part of the country is found the
handsome Libellula lyiichcUa, shown in Fig. 36. It is a
large species with pruinose body, and the wings are each
conspicuously marked with three black patches. This
species is seen very frequently flying over low meadows and
in the vicinity of ponds and rivers. Judging by the abun-
dance of the adults it must be one of the quite important
species as affecting the aquatic life, and the adults must
dispose of many troublesome pests.

Fig. 37. — Leucotermes flavipes: a, adult male; b, terminal abdominal
segments of same from below; c, same of female; d, male, side view, some-
what inflated by treatment with ammonia; e, abdomen of female, side
view; /, tarsus, showing joints and claw; a, d, e, enlarged; b, c, f, greatly
enlarged. (After Marlatt, Div. Ent., U. S. Dept. Ag.)

Order ISOPTERA.

This order is characterized particularly by the thickly
net-veined wings which fold flat upon the back and by the
biting mouth parts and incomplete metamorphosis.

The order includes one family, the Termitida?, in which
there is a remarkable separation of habits, the species living
in communities and showing much the same kind of adap-

ORDER I SOFT ERA

77

tation for community life as is sliown in the ants. 'I'he
colonies usually include a large number of individuals, but
may vary from a few dozen to many thousands. Each
colony also includes several kinds of individuals, some of

Fig. .38. — Leucotermes flavipcs: a, queen; h, nymph of winged female;
c, worker; d, soldier. All enlarged. (From Marlatt, Div. Ent., U. S.
Dept. Ag.)

which are neuters, while others represent the males and
females of normal species. The males and females are
winged at time of maturity, but the wings are broken off
after flight, and thereafter these individuals, like the neuters,

78

LOWER PTERYGOTA

appear to be wingless, although the stubs of the broken-off
wings may be noted. At the time of flight the different
individuals come to rest at different places, so that they
are pretty generally distributed. They then set to work
to form a new colony. This, however, is impossible unless
some of the w^orkers are also located at the same place.
It often occurs that many die off, without establishing a
new colony, for lack of workers.

The colonies are located in the earth, or for some species
upon the trunks of trees, or in some of the tropical forms

Fig. 39. — Leiicotermes flavipes: a, newly hatched larva; h, same from
below; c, egg. All enlarged. (From Marlatt, Div. Ent., U. S. Dept.
Ag.)

large ant hills are built above ground which accommodate
immense numbers of individuals.

The white ants feed upon wooden fil)er and make attacks
upon trees or upon dead timber and are especially destruc-
tive to wooden structures, so that in regions where they are
abundant they constitute a very serious menace to wooden
structures. They also feed very extensively upon wooden
furniture, books or papers in places accessible to them, and
the damage occasioned by such attacks is often very exten-

ORDER ISOPTERA

79

The colonies include as neuters two forms: one, the
workers, having moderately large heads, strong jaws, and
adajited for carrying on the labor of the colony, such as col-

FiG. 40. — Work of white ant (Lciicutcrmc.'i flavijjes) in chestnut.

lecting food, caring for the young, and in fact, all of the
ordinary work of the colony. The other form, called soldiers,
has as its special function the protection of the colonies.

80 LOWER PTERYGOTA

They have enormous heads, strong jaws, and are especially
fitted for attacking enemies that may enter the colony.
They are, of course, helpless against larger kinds of animals,

Fig. 41.— Termites and their work: a, adults working in the stem of
geranium (photograph by Wm, P. Beeching, Jr., Ohio Agric. Exp. Sta.);
b, enclosed gallery suspended from the underside of greenhouse bench
(photograph by J. L. King, Ohio Agric. Exp. Sta.).

but their bite is very severe and they doubtless in this way
serve as very effective guards against a numerous host of
smaller-sized animals.

ORDER CORRODE NT I A 81

The must abuiulant individuals are the workers and tlien
tlie soldiers. Both of these forms never acquire wings.

For this region and for the eastern and southern United
States there is one common species, Leucotermes flavipes
which is distributed as far north as the Great Lakes, to
Boston on the Atlantic coast, and into central Illinois in
the Mississippi A^alley. The colonies of this species are
formed, usually under old logs or stumps, and from these
nests the termites construct tunnels, sometimes for long
distances, to reach dead wood, buildings or other structures
in which they can secure a food supply. Porches, fences,
and all sorts of wooden structures sufi'er from their attack,
but the greatest menace, perhaps, is to wooden trestles
and bridges which are likely to have sudden weight thrust
upon them. In feeding, the ants eat out the inner part of
the timbers, leaving an exterior shell, thus it happens the
timbers are greatly weakened before any indication is seen
upon the surface.

The most effective treatment is to locate the nest, give
it a thorough treatment of bisulphide of carbon to kill out
es])ecially the reproductive individuals, so that the colony
will not be able to multiply.

Particularly the use of stone, brick or concrete foiuidations
in bridges or trestles and the separation of the wooden part
of structures from the earth in localities wdiere white ants
are present will serve as a prevention from their attacks.
In tropical regions the practice is to use stone or metal,
not only for bridges, trestles, etc., but in many places for
railway ties, in order to avoid loss from the termite's attacks.

Order CORRODENTIA.

Family Psocidae. — Book Lice. — These are small insects,
a considerable number of them are entirely wingless, but
there are many species in which the wings are fully devel-
oped. The wings are held in a sloping position, a somewhat
roof-like arrangement over the abdomen, but not folded
flat, and have a rather small number of veins. Their appear-
6

82

LOWER PTERYGOTA

ance is considerably like that of the plant lice, but they
have distinct biting mouth parts. They are totally different,

Fig. 42.— Clothilla.

Fi(i. 48. — Work of Atropos on grain. (Plioto from Ohio Exp. Sta.)

though, in their method of reproduction. The more interest-
ing members of the group are those which are wingless

ORDER MALLOPHAGA

83

and occur in houses, commonly found among books, old
papers, insect collections or herbaria, and which do a great
deal of damage in such places.

The common book louse, Atropos divinatoria, is most
abundant in houses among old books. They are too small
to be pinned, but they can be mounted on micro slides to
good advantage, for study with the microscope. They are
about one-sixteenth of an inch in length, rather flat, nearly
white, antennffi slender, and eyes quite small. Their man-
dibles are strong and they feed on the mucilage and glue or
paste of book bindings, on the tissues of preserved insects,

Fig. 44. — AlrujM:^ difinaloria.

and they are quite detrimental to collections of plants in
herbaria.

They may be destroyed l)y fumigating with bisulphide
of carbon for half an hour or so. They are so very small
that it is almost an imi)ossibility to exclude them entirely
from any place.

Order MALLOPHAGA (Bird Lice).

This order includes the biting lice infesting birds and
mammals. They are usually hard and horny and much
flattened. They possess mandibulate mouth parts adapted

84 LOWER PTERYGOTA

to cutting and biting the hairs, feathers, epidermal scales,
or excretions on the bodies of their hosts. The mandibles
are situated in most forms underneath the head and near
the centre, the clypeus projecting and forming the most
anterior portion of the head. The labrum is present and
the maxillary palpi are prominent in a part of the group.
The eyes when \'isible are located back of the antennae.
The antennae are five-jointed except in Trichodedes, where
they are three-jointed. The thorax is generally narrow and

Fig. 45. — The cuninion hen louse (Menopon pallidum). Greatly
enlarged. (Banks, Div. Ent., U. S. Dept. Ag.)

frequently but two di\'isions are apparent. The legs are
adapted to clasping (Philopterida') or to running (Liothe-
idse), the tarsi in the first case being short and in the latter
case being long, well adapted to running, and provided
with two claws. The members of the first division occur
on both mammals and birds, those of the second, except
Gyropus, are limited to birds. Wings are entirely wanting,
and the abdomen contains nine or ten segments and is
usually oval in shape.
The eggs are glued to the hairs or feathers of the host

ORDER MALLOPHAGA

85

animal and open with a circular cap or lid at the free end.
The larvae are less flattened, shorter in proportion, and
without the hardened parts common to the adults, covering
a part or all of the surface. The length of life and rapidity
of multiplication has not been determined accurately for

Fig. 46. — Trichodedes scalaris (biting cattle louse). (Bull. 5, Fig. 134.)

these insects and the habits of the insects make any such
determination a matter of considerable difficulty.

While it is, of course, very desirable that a more complete
knowledge of the life history of the species be secured, it
may be considered as already established that all the species,
with no know^n exception, pass their transformations on the
body of the fowl, and that, unlike the mites, they may be

86 LOWER PTERYGOTA

attacked with the assurance that eggs and newly hatched
young are not developing in some out-of-the-way corner.

Moreover, the observations made on the length of time
required for the hatching of the eggs indicate that they
require a number of days at least, so that in repetition of
treatments intended to kill individuals hatched since a
former treatment a period of ten days to two weeks ma>' be
counted on as probably short enough.

>

Fig. 47.-

-Trichodectes parumpilasus (biting horse louse). (Bull. 5,
Fig. 133.)

It should always be borne in mind that lice must grow
from eggs laid by the adult louse, and can never originate
from filth or other matter. Chickens hatched in an incuba-
tor should be absolutely free from lice and remain so until
brought in contact with a lousy hen or put in a lousy chicken
house.

The effect of these lice may be less important than the

ORDER THYSANOPTERA 87

suctorial lice, or the sucking ticks or mites; but judging
from the serious results following the efforts of the animals
to rid themselves, and from the known irritation due to
anything crawling among the hairs or feathers, it cannot be
(K)ubted that they cause much annoyance and inconvenience
to the creatures that become their involuntary supporters.
The biting lice of cattle and horses are annoying pests
and demand the attention of the stockman.

Order THYSANOPTERA.

The species of this order are all very small and have
mouth parts intermediate between the biting mouth parts
of the Orthoptera and the suctorial mouth parts of the
Hemiptera. In some respects they may be considered as an
intermediate group between the Orthoptera and the Hemip-
tera, but not as a distinct connecting link between the two,
because in the matter of wings they have a specialization
of their own. They are minute, all very small, the largest
not over one-eighth to one-fourth of an inch in length.
Many are not over one-sixteenth of an inch long. They
have very slender bodies and slip around readily between
the parts of the blossoms of many different kinds of plants.
The different stages may occur in the bloom, and they feed,
at least in large part, upon the soft tissues of the parts of
the blossoms, puncturing and corroding them so as to secure
the juicy contents.

The mouth parts are drawn out in style-like form. Their
structure is partially like that of Hemiptera, but the styles
are not produced beyond the length of the head. They are
not capable of cutting and biting as the mouth parts of the
grasshoppers, nor are they strictly suctorial organs. The
wings are characteristic. In one division the wings are
narrow, with few veins and provided wath quite long marginal
setse which furnish a large part of the area of the wings.
The hind wings of this form also have setse but no veins.
Another division has wings very simple, without any vena-
tion, and provided with enormously long sette. They are

88 LOWER PTERYCOTA

fringe-winged forms, a characteristic structure. x\nother
character almost equally distinctive is found in an aborted
tarsal joint modified into a bladder-like expansion of the
tarsus. This joint is evidently a modification from the
ordinary form with claws. Bladder-foot is one term applied
to this group and Physopoda is the name given in some text-
books, based on this particular structure.

The life history of the group in general is rather sim])le.
The adults deposit eggs at dift'erent periods through the
summer, the generations being somewhat irregular, often
three or four in a summer. The eggs are rather large for
the size of the insect and somewhat ovoidal or oblong in
shape, almost transparent. They are deposited on the
foliage or bloom of plants, and hatch quite promptly. The
larv?e develop gradually by successive moults, without
any striking metamorphosis, until they reach the adult
stage when wings are developed. Between the larval and
adult stages is a stage of quiescence; parts, including the
antennae and legs, are almost immovable. This may be
looked upon as a development along the line of the more
striking metamorphosis in other cases. The eggs are
deposited by means of an o\ipositor that differs in the two
subgroups of the family. In one case there is a saw-like
ovipositor with blades that glide on each other and enable
them to push eggs into soft tissues. In the other division
the ovipositor consists of the elongated tubular abdominal
segments. The latter is a more simple condition, but the
former is more primiti\e. The latter probably results from
reduction, the saw-like structure being lost. The dift'erence
in egg deposition amounts simply to position in which
eggs are laid: in the first instance they are laid more or less
within the tissue, in the second instance on the surface.

For the first group, Terebrantia, the common Thripidse
occur in clover, Compositce, apple blossoms, milkweed, etc.,
also in wheat blossoms. The food plant is determined simply
by the flowering season. The most abundant is the wheat
thrips, Thrips tritici; this is an economic species, causing
some damage.

ORDER THYSANOPTERA

89

In the spring they are found in apple bloom and a large
proportion of the blossoms are infested, as high as 80 per
cent, in one instance having been observed to be so damaged
as to render blossoms infertile. They also occur commonly

Fig. 48

Fig. 48. — The pear thrips (Eulhrips pyri) : ovipositor and end of abdo-
men from side. Much enlarged. (After Moulton, Bur. Ent., U. S. Dept. Ag.)

Fig. 49. — The pear thrips (Euthrips pyri): larva. Much enlarged.
(After Moulton, Bur. Ent., U. S. Dept. Ag.)

in strawberry bloom, and the injury to the bloom appears
to result in the distortion of the berry known as " buttoning."
When exposed they can be killed by spraying with kerosene
emulsion.

90

LOWER PTERYGOTA

Pear Thrips (E nth rips pyri). — The pear thrips has been
a serious jjest in California, attacking beside pear a number
of the rehited fruits. Its attack is directed largely against
the bloom and the loss of fruit is serious. Contact sprays
are only partially effective, as the insect is protected so much
of the time within the parts of the bloom.

Grass Thrips {Aphanaihrlps striata). — The grass thrips is
an extremely abundant species in the northeastern United

Fig. 50.— The pear thrips {Euthrips pijri) : nymph or pupa. Much
enlarged. (After Moulton, Bur. Ent., U. S. Dept. Ag.)

States, and has been reported as destructive to oats in
Canada. It attacks the upper part of the plant and its injury
shows, especially in the blasting of the heads of grass and
oats. In grass this is called "silver top," a condition of
whitening and withering of the upper stem and seed head
which is probably produced by other insects as well as thrips,
but which is no doubt in large measure to be credited to
these almost invisible little pests.
Another species is Thrijjs tahaci — known now as onion

ORDER THYSANOPTERA

91

thri]is. It occurs on quite a large variety of plants. It is
similar to Thrips iritici in size, but different in some micro-
scopic details. It is injurious to onions. Massachusetts,
Iowa, Colorado, Rhode Island, and Ohio have all reported

Fig. 51. — The pear thrips {Euthrips pi/ri): adult. Much enlarged.
(After Moulton, Bur. Ent., U. S. Dept. Ag.)

extreme injury from this species. The degree of injury is
determined in large part by temperature, moisture, etc.
It occurs on many plants besides onions. In dry seasons
it becomes very injurious to the onions. The leaves wilt
and show whitening, and the injury is easily recognized.

92 • LOWER PTERYGOTA

The life history is a matter of adaptation to different
])lants. There are probably several generations in one
summer and liibernation in mature larval or adult stage.

Mullein Thrips {Phloeothrlps verbasci). — ^The mullein thrips
has a definite restricted food plant and the herbivorous
character of the insect can be easily established. It is a little
l)lack species found in mullein ])lants the year through.
In early spring they are found among the bases of the mullein
leaves. They seldom try to fly, but creep about among the
fine hairs of the mullein leaf. They are very common in the
mullein plants and there are very few plants without them,
so examples may almost certainly be found wherever mullein
occurs. The eggs are laid soon after the leaves are Avell
started in the spring and there is a pretty definite brood.

The adults of this brood mature about the time the blos-
soms appear, this being the softest portion of the plant
at this period. Later on adults in resting period are found
in seed pods or secreted around the base of the plants.
There are two generations in the summer fthe adult individ-
uals appearing first in the spring, then again in the sum-
mer, and again in the autumn. They do not do any great
damage to the leaves, although they feed upon this plant
exclusively.

Another species, Phloeothrips nigra, occurs in clover
bloom. It is a black species and evidently restricted to
clover. The larva is bright red and often found during
the winter. They feed on part of the clover bloom and so
far as it has any eft'ect, is destructive to the clover. One
species is credited with feeding upon the grape Phylloxera.
If it does this it is an exception to the usual food habit of
the family. It possibly may feed ordinarily upon the tissue
of the gall and exceptionally on the plant lice that occur
within the gall.

The group as a whole is to be considered as herbivorous
rather than carnivorous, and injurious when occurring on
useful plants.

/ chaptp:r v.

ORDER HEMIPTERA.

The Ilemiptera constitutes one of the large orders of
insects and includes some of the very important economic
species, and some of the very striking specializations in
insect life history including extremes in different kinds of
environment, life habit, and one of the most striking extremes
in the matter of reproduction and de\'elopment.

The essential character of the order is found in tlie devel-
opment of the mouth parts, there being also other distinct
differences in the matter of wing structure and some other
parts of the body. The mouth parts are adapted for suction
in the larval as well as the adult stages. This represents a
more radical change of these parts than when the mouth
parts are different in different stages. The modification
in the mouth parts consists in the change of the mandibles
and maxillse into bristles or setse which serve to puncture
the tissues of the plants upon which the insects feed by
l)umping out the juices. The labrum (epipharynx of some
autliors) is present as a rather aborted structure; the labium
is modified into a sheath for the bristles or setse and is usually
three- or four-jointed. These segments are fitted together
to form a sheath or tubular or furrowed organ within wliich
the bristles or sette play back and forth as they are dri\en
into the tissues which constitute the food of the insects.
Within the group there are differences in wing structure
which enable us to separate the group into two very distinct
suborders, and in some cases three are recognized, the third
including only parasitic forms.

The two main suborders are tlie ITomoptera and the
TIeteroptera, the first including those forms which ha\e

(93)

94

ORDER HEMIPTERA

membranous or opaque, but homogeneous wings; tlie second
liaving the front wings thickened at the base and membranous
at the apical portion. The Heteroptera are often given first
as if more primitive, but the Homoptera appear to have the
most fundamentally primitive character. The venation
of the wings and the position of the head particularly seem
of more primitive character than in the Heteroptera.

The third group, Parasita, includes the suctorial lice;
the wings are lost, beak is single-jointed, and sette are very
much elongated and tubular. They are restricted to the
warm-blooded vertebrates, mammals.

Fiu. .52. — The periodical eicadii (Tihiccn scptcndccem): n, adult; b,
same, side view; c, shed pupal skin. Nat\iral size. (After Mailatt, Bur.
Ent.. U. S. Dept. Ag.)

The Homoptera are divided into two divisions, Auch-
enorhynchi and Sternorhynclii. In the first group the beak
is free, not attached to the sternum, and may be moved
readily from the head as its base. In the second grouj) it
is fused into the sternum and the base connected with the
head at about right angles to the sternum. This latter is
a s])ecia]ized condition and must be derived from the simpler
condition where the beak is free.

In the Auchenorhynchi the Cicadidte are one of the most
prominent families, which is apparently rather generalized
in its features. They show specialization in their life his-

ORDER HEMIPTERA

95

tory. The most common species, or, for the Homoptera, one
of the most widely known, is the seventeen-year cicada,
which is especially remarkable on account of its long life.
The seventeen-year cycle is certainly known and well estab-
lished by observation. The adults appear at these periodical
intervals in the latter part of June and they are apparent

Fig. o3.—Tibicen septendecem: adults on two-year-old apple tree.
(Photo from Ohio Exp. Sta.)

during- this stage when they feed very slightly on vegetation,
mate and deposit their eggs during a period of four' or five
weeks, though they are seen in great abundance for a period
of only a few days. They are noticeable from their size
and from the very loud note that is produced by the males.
The song is a long-drawn-out sort of screech and is produced

96

ORDER HEMIPTERA

by an organ located in the base of the abdomen, covered
by the wings when folded and slightly covered from below
by an operculum. The structure of the drum is somewhat
flattened and inside is a cluster of muscles attached to the

j4. — Tibiccn scplcndeccin: adults oN'ipositiiit
(Photo from Ohio Exp. Sta.)

abdominal wall. Their contraction serves to draw this
membrane in, after which it immediately resumes its former
position and when repeated rapidly this causes a vibration,
producing a whirring or buzzing note which varies in inten-
sity with the rapidity of the vibrations. Its purpose has

ORDER HEMIPTERA

97

been interpreted as that of a mating call, hut no auditors-
organ has been described. The females deposit eggs in
twigs of trees, punctiu-ing the trees with little furrows, which
result in splitting the bark, and the twigs often die. The

-Tihicen septendccem: twigs broken from egg deposition
(Photo from Ohio Exp. Sta.)

eggs hatch five or six weeks after their deposition. The
larvse drop from the twigs and pass into the ground and from
that time on for almost the next seventeen years are out of
sight and are growing gradually, moulting occasionally,
7

98 ORDER HEMIPTERA

probably once a year at least. They feed for the most part
on the roots of trees and shrubs and woody plants occurring
in their location. When trees are cut away after the eggs
are dejjosited, some of the nymphs doubtless fail to develop,
but there are some that become mature.

The uniformity in their appearance ma>- be accounted
for by the fact that those that did not come out at a definite
time had little chance of l)reeding and reproducing. They
occur throughout the eastern United States and the seven-
teen-year form mostly to the north of the latitude of the
Ohio river. To the south of that latitude there is a thirteen-
year form. They do not occur over the whole area of the
country in which they may be considered as native, there
being portions where they do not occur at all, other places
where they occur twice in seventeen years, and still other
places where they occur three times in seventeen years.
They may be descendants of a generalized mass of cicadas
with a shorter life period. Just why they have been retarded
is another problem. Their subterranean habit and conse-
quent slow growth might serve to prolong their life.

The dog-day cicada Avhich appears commonly in August,
lays its eggs in twigs of various trees, but the growth of
the nymph is much more rapid. The injury is the same as
in the seventeen-year cicada. The attacks of the adults
in young orchards are sometimes serious.

After the Cicadidse the Membracidse are perhaps the
most generalized, though they present a specialized struct-
ure of the thorax. They are called treehoppers, the majority
inhabiting trees and shrubs, a few only occurring on her-
baceous plants. The specialization of the thorax is shown
in various ways. The prothorax is the greatest part of the
body visible from above. There are many variations and
these result in a great many forms of mimicry and protec-
tive resemblance. Some forms have the ])osterior part of
the prothorax broken up into globular pieces simulating the
body of an ant. In some cases there are three large knobs
which hang out from the central part and probably resemble
parts of the tree on which it occurs. They take on the

ORDER. HEMIPTERA

99

greatest variety of forms, many very grotesque. The group
is large and includes many species. There are probably
fifty species in the latitude of the Northern States.

One of the most common is the buffalo treehopper,
Ceresa buhahis, which abounds on thorn, ap})le and maple
trees and is frequently found on other vegetation. It is
of an apple-green color, with faint, light yellow mottlings

Fig. 56. — Buffalo treehopper: n, female; b, enlargement of foot;
c, antenna; d, wing; /, g, ovipositor; /(, ?, terminal segment of male abdomen;
e, terminal segment male taurina. (After Marlatt, Bur. Ent., U. S. Dept.

Ag.)

or specks, distributed over the pronotum. The pronotum
itself stands out in two prominent horns. It extends back
in a very pronounced spine. The eyes are quite prominent
and stand out at the sides of the head. There are four species
closely related, but this one is the most abundant. Its life
history is quite characteristic for the group. They are
single-brooded and the winter is passed in the egg stage;
the eggs are deposited in twigs of various trees in little slits

100

ORDER HEMIPTERA

of the bark, with slightly crescent-shaped scars, and eggs
are arranged in parallel rows, causing damage to the trees.
The young hatch in the spring and early summer and as
hatched they are quite grotesque. The body is shaped
something like that of an adult, but along the dorsal line there
is a series of sharp spines, the divisions of the body are fairly
well marked and the divisions of the abdomen are distinct.

Fig. 57.- — Ceresa bubalus. Twig of apple showing: a, female at work;
b, recent egg puncture; c, bark reversed with eggs in position, slightly
enlarged; d, single row of eggs still more enlarged; e, wounds of two or
three years' standing on older limbs. (After Marlatt.)

There is no such expansion of the prothorax as in the adult.
They moult several times and with the aquisition of the wings
the pronotum becomes fully expanded. The moults occur,
mainly in June and July and the adults appear usually in
the latter part of July. Deposition of eggs occurs rather
early in the fall. A considerable part of the year is spent
in the egg stage. Injury is caused by pumping the sap and

FAMILY FULGORID^

101

is limited to a rather short i)eriod, but the injury caused
by puncturing the twigs for egg deposition does not fully
appear for a year or two after the eggs are deposited. The
scars and distorted growth of the twig may seriously dis'^
figure and weaken the branch. It is rather difficult to apply
any distinct remedy because they occur on so many different
kinds of plants. Cutting off the infected twigs would be
possible but hardly practicable on any large scale. The

Fig. 58 Fig. 59

Figs. 58 and 59. — Ormenis pruinosa Say: at right, a and b, adults; at
left, a, eggs, much enlarged; b, eggs in bark; c, twig with eggs. (After
Lugger.)

application of kerosene emulsion would be effective at the
same time that other forms are developing, thus killing off
more than one si)ecies at one time.

Family Fulgoridae. — The family Fiilgorul(F presents ex-
treme specialization in some directions. These occur in the
head region instead of the prothoracic region. In one
of the most extreme forms the head is spread out into a
great peanut-like structure, and in one form there is an

102

ORDER HEMIPTERA

appearance of a large spot on this head portion, and in one
species there is stated to be phosphorescence. The thorax,
wings and abdomen have for the most part normal character
or some variation in the wings. It is an enormous family,
especially represented in the tropics. There are few strik-
ing members of the group represented in northern latitudes.
A good many of the forms are inconspicuous. A few special
forms representative of the group may be mentioned.

Fi(i. 60.— Fulgorid. (Original, from drawing by Miss Edith Hyde.)

Otioceras. — Otioceras is as elegant a little insect as can
be found in any group of insects. They appear very much
like delicate little moths. The head is drawn out into a
plowshare-shaped form. The eyes are ])rominent and the
antenna? very peculiar, with little flabella-like appendages.
The eyes stand out at the sides of the head, the wings run
back in a moth-like form and are quite delicately veined
and marked. These occur mainh' on hickories or closelv

FAMILY FULGORIDM 103

related trees, in August and September or October. The\'
may be obtained by l)eating the trees over an umbrella with
a stick. The genus includes six or eight common species.
They are quite similar in general appearance.

Delphacidse. — The Delphacidie are characterized by the
presence of a large, movable spur on the end of the tibia,
and tibia and tarsal joint run out with spines. A specialized
appendage for attachment to twigs, stems of grass, etc.,
enables the insects to jump more readily. This is a charac-
teristic structure for this group. These hoppers occur
abundantly in low vegetation, especially on grasses and
some species are abundant enough to be detrimental, as for
instance, the corn Delphacid (Dicmnotroins maidis), and the
sugar-cane hopper, which has been extremely destructive
in the sugar plantations of the Hawaiian Islands. Our
species occur sometimes in blue-grass meadows, and do some
damage. They are minute, varying in size from one and
a half to two millimeters, to four or five millimeters in length.
They present a great variety of modification in wing develop-
ment. Some are dimorphic. There are some in which the
hind pair of wings are wanting or not full-sized, some in
which front wings are reduced entirely or to mere rudiments.
This occurs first in the females, but also in some species in
the males. The greatest amount of reduction appears to
occur in those which live where food supply is abundant
and flight becomes unnecessary. There ma>' be a summer
generation without wings and a fall generation with wings.
One other interesting feature is the fact that they are para-
sitized in a peculiar manner. Certain Hymenopterus para-
sites deposit eggs on the bodies of these and larva? are pro-
duced in a sort of sack extruded between the segments of
the abdomen, and within this sac the larva? develop. These
parasites may have some value in reducing the number of
the hoppers.

The eggs are deposited in the leaf or stem of grasses, etc.,
and the larvse hatch from these and feed on the plant
attacked. The stages of development are gradual and there
are one or two broods annually for the most of the species.

104

ORDER IIEMIPTERA

Some of the forms have juhilt liibernation and others egg
hibernation.

Family Cercopidse. — The CercopidcF is a family that has
few economic s])ecies. • They differ from the Fulgoridse in
having the head and thorax rather normal in shape, first
pair of wings usually thickened opaque and ^Tnation not
very conspicuous. The thorax is well developed, the tibia
terminates in a prominent crown of spines and no spines

Fig. G1.

Aphrophora i-notata Say: a, from above; /), from side.
(From Lugger, Minn. Ann. Rept. 6.)

on the sides of the tibia. These inchide the little frog hop-
pers or "spittle insects." The hxrvte suck the juices of the
plants on which they occur and pump out more juice than
they have use for and extrude it from the body in fluid form
and set air free within this juice, making the frothy mass
which covers the entire body of the larvae. These masses
are found hanging on the stems of plants very frequently
during the summer. After they ha\e passed through the

SUPERFAMILY JASSOIDEA 105

larval and i)iipal stages they do not secrete any such frothy
masses.

Superfamily Jassoidea. — The superfamily Jassoidea in-
cludes several subdivisions of considerable importance. They
abound particularly on low vegetation, and some are grass
feeding, others tree inhabiting. They difl'er from the Ful-
goridte in the more specialized and compact head and
thoracic region and in the more distinctive character of the
hind tibia which is more prismatic in form and with two
rows of spines and without any circle of spines at the ti]).
The subdivisions are separated by means of the venation
of the wings, and by the head parts. There are four fairly
distinct families.

The life histories are somewhat complex. Some species
have a single brood each year, others two, others apparently
three. Some hibernate as adults, many as eggs, some
apparently in partially developed nymphal stages. Some
of the striking examples are the grass leafhoppers, forms
that live continually in the grass and suck the sap, causing
a considerable decrease in the crop, reducing quantity and
quality of the nutritive contents of the grass leaves. In
some the individuals are extremely abundant, one to two
millions to the acre.

The life histories are much the same throughout the group,
but not many have been worked out in detail. The group
stands as one of the most specialized of the Homoptera
that have the primitive condition of the mouth parts.

The term vertex is used for the upper surface of the
head between the eyes and extending to the front border,
which may merge gradually into the front or the face. The
frons, or front, is the part of the face lying between the
sutures and extending down nearly to the lower border.
At the sides of this are portions next the eyes, which are
termed the cheek, and below the front a part called clypeus,
at the sides of which are the lorse. The central part of the
body which bears the wings and legs is termed the thorax,
and the upper portion of the first segment is known as the
pronotum. The front wrings are termed elytra and are

106

ORDER HEMIPTERA

usually' thicker and stronger than the hind pair, which are
concealed beneath the front ones when at rest. The abdo-

FiG. 62. — Explanation of terms, from drawing of Athysanus obtutus: a,
female from beneath; b, from side; c, from above; d, female genitalia;
e, male genitalia; /, larva or nymph; g, eggs, showing developing larvae;
h, egg, enlarged; i, eggs in position beneath sheath of grass stem. Structural
details: ac, apical cells; a.ac, anteapical cells; cL, clavus; clyp., clypeus; cox.,
coxa; fr., front; fern., femus; lor a, lora; ov., ovipositor; plate, plate; pr.,
prothorax; py. (tf), ry. {P), pygofer; tar., tarsus; lib., tibia; v., vertex;
vs., terminal ventral segment; valve, valve. All enlarged. (After Osborn
and Ball.)

men may be entirely hidden above by the wrings, but in
short-winged forms is more or less exposed. The parts of
greatest importance on the abdomen for purposes of descrip-

SUPERFAMILY JASSOIDEA

107

tion are the terminal segments, inekuling tlie genitalia. In
the female the last ventral segment is frequently of a par-
ticular shape or structure for dift'erent species and in many
groups is of the greatest service for description. It is fol-
lowed by the sheaths of the ovipositor, this latter being a
narrow, saw-like pair of blades, extending to the tip, some-
times considerably beyond the tip of the sheaths. The
males have a terminal segment beneath a modified segment,
called the vah'e, which is followed by two movable pieces
called plates. Above these, forming the sides of the last

Fig. 6.3. — The clover leafhopper (Agallia sanguinolenta): a, adult; h,
nymph, side view; c, nymph, dorsal view; d, face; c, elytron; /, female
genitalia; g, male genitalia. All enlarged. (After Oshorn and Ball.)

segment, are the pygofers. A ready understanding of these
various parts will be helped by a study of the accompanying
figure, in which they are located and named. For the
different stages of insects the usual terms egg, larva, or
nymph, ])upa, and adult are used, as these are sufficiently
definite in indicating the steps of development from the
egg to the mature form.

Bythoscopidse. — The Bythoscopidcp include forms whicli
are for the most part found upon trees or woody plants,
sometimes in great abundance and which doubtless occasion
considerable injury, although the eft'ect in any particular

108

ORDER HEMIPTERA

case may not be very apparent. The common species
affect willows.

Idiocerus alternatus lays eggs in the bark and passes
throngh two generations each year.

Fig. G4.— Glassy- winged sharpshooter: a, adult?, seen from above; b,
side view; c, venation of forewing, enlarged; d, antenna?; e, section of
hind tibia; /, 9 genitaha, more enlarged; g, serration of ovipositor, still
more enlarged. (From Howard, Bur. Ent., U. S. Dept. Ag.)

Clover Leafhopper, — Another form of considerable eco-
nomic im])ortance, the clover leafhopper, is a very common
pest of clover and alfalfa and has been noted as troublesome
in sugar-beet fields.

Family Tettigoniellidse. — The family TettigoniellidoB in-
cludes an enormous number of species occurring in the
tropics and a considerable number of common forms through-

FAMILY TETTIGONIELLIDJi

109

out tlie temperate regions, among tliem a i)articular species
known as the sharpshooter, Oncometopia undata, which
discharges droplets of hquid, so that when the insects are
abundant, the tree in which they occur may shed consider-

FiG. 65.- — Drceculacephala mollipes: a, adult from above; b, face, much
enlarged; c, vertex and pronotum ,^; d, female genitalia; e, male geni-
talia; /, wing; g, h, nymphs. All enlarged. (After Osborn, Bur. Ent.,
Bull. 108.)

able liquid, and this leads to the name "weeping tree."
The glassy-winged sharpshooter, figured here, has a similar
habit.

Tenderfoot Leafhopper. — A species which is very abundant
in grass lands is the tenderfoot leafhopper, Drcectdacephala

no

ORDER HEMIPTERA

mollipes. This is light grass-green in color, quite slender,
has a very sharj^ly pointed head, and is very well protected
on the blades of grass both by its color and form. It occurs
on a great variety of grass plants and is known all the way

Fig. 66. — The shovel-nosed leafhopper (Dorycephalus platyrhyrichus: a,
female; b, male; c, face; d, female genitalia; c, male genitalia; /, eggs in
grass stem; g, eggs; h, egg, more enlarged and showing developing nymph;
i, j, k, I, different stages of growth of nymph. .\11 enlarged. (After
Osborn and Ball.)

from Canada to Central America. TJie nymphs have
fairly well-marked longitudinal stripes arranged as shown
in the figure, but are much less commonly observed than
the adults.

FAMILY JASSIDJi

111

Family Jassidae. — The family JassidcB, including the forms
which ha\e the ocelli located in the margin of the head be-
tween the vertex and front, is very largely represented in
temperate regions and many of the species affect important
cultivated crops.

Fig. 67.— The inimical leaf hopper (Deltocephalus inimicus): a, adult;
6, face; c, vertex and pronotum; d, female genitalia; e, male genitalia;
/, elytra; g, nymph. All enlarged. (After Osborn and Ball.)

Shovel-nosed Leaf hopper { Dori/cephaln.'^ plaiyrhynchus). —
The sho\el-nosed leafhoi)per is a rather large species with
an enormous prolonged head and is found upon the wild
oat, Elymus canadensis. The eggs are laid beneath leaf
sheaths, a considerable number in a compact row and the

112

ORDER HEMIPTERA

nymphs on hatching begin feeding at once upon the grass.
The adult females have short wings and do not jump or fly
rapidly.

Inimical Leafhopper (Deltoccphalu.s utimicu.'i). — The in-
imical leafhopper is perhaps the most abundant species
throughout the northern United States where blue grass
is a common pasture grass. While abundant and almost

Fig. 68. — The inimical leafhopper (Dcltoccphalus inimicus) : iiymphal
stages: o, newly hatched; b, c, d, later stages, the details of tarsal appen-
dages shown below. All enlarged. (After Osborn, Bur. Ent., Bull. 108.)

universal in blue grass, it may also be found upon other
species of grass and also in wheat and alfalfa. This sj)ecies
is so abundant and wide-spread that it is almost impossible
to sweep a patch of blue grass in any locality from INIaine
to Washington, and south to northern Tennessee, without
finding it in abundance. The nymphs pass through five
distinct stages with differences in the shape of the head and
development of wing pads and an increase in the number

FAMILY JAS,SID.fJ

113

of minute appendages on the first tarsal segment, as sliown
in the figure.

The destructive leafhopper (Afhi/mnus exitiosus), was
first noticed as a pest in grain fields in the Southern States,

Fig. 69. — The destructive leafhopper (Athysanus e.iitiosiis) a, adult
female, dorsal view; b, head and pronotum of male; c, face of female, d,
female genitalia; e, male genitalia; /, wing; g, eggs disserted from female;
/), l, j, three stages of nymphal growth. All enlarged. (After Osborn,
Bur. Ent., Bull. 108.)

but is now knowm to be distributed throughout the larger
portion of the United States, which likely is the result of a
dispersal from the southern localities with possible intro-

8

114

ORDER HEMIPTERA

duction from the West Indies or Mexico in some not distant
period.

Six-spotted Leafhopper. — The six-spotted leafhopper occurs
in abundance throughout the country and is also a common
species in Europe. Whether its common distribution is due
•to original extent of the species, or whether the species has
been introduced into America in modern times, is impossible
to say. It develops rather rapidly and apparently passes
through two or three generations at least in northern locali-
ties, and possibly three to five in the more southern States.
It is especially injurious in oat fields.

Fig. 70. — The six-spotted leafhopper {Cicadula-6-nolata): a, adult;
b, face; c, wing; d, female genitalia; e. male genitalia; /, nymph. All
enlarged. (After Osborn, Bull. 108, Bur. Ent., U. S. Dept. Ag.)

Typhlocybidse includes a group of minute forms most of
which are found on trees or woody plants, but certain ones
occur on grains or grasses. The most familiar and destruc-
tive forms are the group of leafhoppers which cause wither-
ing and whitening of grape-vines in the midsummer and
autumn. Typhlocyha comes includes several varieties, all
of which are destructive to grapes, the nymphal stages
being found usually on the under side of the leaves, and the
effect of their puncturing shows in minute white spots on
the upper surface of the leaves.

FAMILY PSYLLIUM

115

Apple Leafhopper (Empoasca mali). — The apple leafhopper,
another very destructive form, affects apple and other
fruit trees. Occasionally it is destructive to alfalfa, cow
peas, potatoes and beans.

Fiu.

1. — Pear-tree psylla: adult female — natural size indicated by side
line. (From Marlatt, Div. Ent., U. S. Dept. Ag.)

The Sternorhynchi include those Homoptera that have
the beak fused into the sternum. The group contains some
remarkably specialized forms of insects and there are four
distinct families, closely linked together by connecting
forms.

Psyllidae. — The Psyllidce seem closely related to the
cicadas. The shape of the body and head is like that in the

116

ORDER HEMIPTERA

cicadas, wings specialized, and they differ in the beak
being fused into the sternum. They are descended from a
generahzed insect like the cicada in character. The prin-
cipal line of specialization has been in the fusion of the beak
and sternum. It stands out at almost right angles to the
prothorax, between the front legs.

All of the species are quite small. Some feed directly on
the surface of plants. Others present a distinctly specialized
food habit, producing galls on various trees, expecially
on the hackberrv.

Fig. 72. — Pear-tree psylla: n, egK; b, larva, hut greatly enlarged.
(From Marlatt, Div. Eiit., U. S. Dept. Ag.)

A common and destructive species in the Eastern States
is the pear psylla which causes serious loss in pear orchards.

One of the most common is Pachi/psi/Ua ceJiidis-mamma.
The larvffi are found in cavities in the galls; the galls are
formed by the deposition of eggs on the surface of the leaves
and the stimulation of the leaf cells. The life-cycle must
lie adapted to the growth of the leaf on which it occurs.
In the gall, when dried up in the fall, are found either adults
or mature nymphs. The adults usually emerge and secrete
themselves in fallen leaves, etc. The adults appear in the
spring at about the time that the hackberry leaves are ex-
panding and (le])osit eggs on the surface of the leaves, and

FAMILY APIIIDIDJE

117

during the rapid growing period of the leaf these galls are
developed and tiie larvje are growing within them. There
is a single generation during the year. This is the plan of
development for practically all of these psyllid galls. A
niuuher of different kinds occur on hackberry trees. They
are readily identified by the character of the galls produced
on the trees. iVIost species are located on the leaves, but
some species form a structure on the twig l)y a modification

"-•^

.*«^*-^

^^.

^^^^^"^

-^

^•^J

iMWk

^7

A

^

-Jr

Wl^lf ■■■■k^

^HP . ^

-^\

"am

i^

F''

M

|H

r^

<^

\

Fig. 73. — Pear-tree jisylla: nymph greatly enlarged. (From Marlatt, Div.
Ent., U. S. Dept. Ag.)

of the bud. There is a distinct specialization in the matter
of food supply which characterizes a large part of the family
Psyllida^. Stimulation of the plant tissues is produced by
the action of the larvtie in puncturing the cells.

Family Aphididse. — This family is specialized particu-
larly with reference to the mode of reproduction. It agrees
with other forms of the Sternorhynchi in having the beak
apparently fused with the prosternum, so that the beak
appears to arise from the sternimi. There is a reduction of

118 ORDER HEMIPTERA

the venation in some genera. The forms with the most
numerous veins are the more primitive and the fe\ver-^■eined
forms must be regarded as speciaHzed.

The nectaries, or so-called "honey tubes" or "cornicles,"
are structures peculiar to Aphididse, located on the hinder
part of the abdomen. Fluids may exude from their tips and
much difference of opinion has existed as to their functions.
Some think that the fluids are used as a means of defense.
It is now generally accepted that the "honey dew" emitted
by plant lice is discharged from the anal opening, and con-
sists of slightly modified sap from the plant to which the
aphid is attached. It is sweet and may form some sugar on
evaporation and is much sought by ants and some other
insects.

Aphids are characterized by the appearance of several
successive generations which are devoid of wings and closely
confined to their host plant. Reproduction is in large
measure parthenogenetic, many generations occurring with-
out the appearance of the sexual forms. A rapid rate of
reproduction is provided for; sometimes as many as ten or
twelve generations in a season. It has been estimated that,
starting with one stem-mother in the spring, her progeny
during the season, if not curtailed, would amount to bil-
lions or trillions of individuals, sufficient to overrun the
world or to equal in bulk of organic matter the population
of China. The agamic eggs are termed "pseudova," and
are often developed and hatched before being extruded
(ovoviviparous).

No general statement can be made which will properly
cover the life history and development of all species, but in
general, and in the temperate latitudes particularly, hiber-
nation takes place in the egg stage. As the usual thing these
eggs are fertilized and occur on the plant which was the last
host of the species in the autumn. In the spring these eggs
hatch into stem-mothers, which are asexual individuals and
for which there is no corresponding male. They do not
require fertilization and they produce either eggs or living
young. The young produced are ordinarily wingless when

FAMILY APHIDIDJE 119

they mature and as many as two or three generations of
these agamic apterous forms may be produced. Next,
alate (winged) forms are produced, usually asexual, to pro-
vide for a migration of the species to another host plant.
As a general thing these winged migrants usually produce
mainly wingless, agamic forms. In the autumn a winged
form appears (usually asexual) which permits the return of
the species to its original host. Frequently with aphids
having alternate food plants the spring and autumn host
plants are perennials — woody or shrubby plants, the sum-
mer host plant an annual. A number of cases, however, of
alternation between woody plants are known. An example
of the former is seen in the case of an apple-plant louse,
Siphocoryne avence, which winters over in the egg stage
on apple trees, the spring forms occur for two or three
generations on apple and then apparently disappear; in
reality they migrate to wheat and breed on it during the
summer. With the ripening of the wheat the lice leave
and return to the apple. In the case of the hop-plant louse,
Phorodon humuli, the spring and fall forms occur on wild
plum and the midsummer forms by migration on the hop
plants, which accounts for their very sudden appearance
and in such large numbers in the hop vineyards in summer.

The return migration in autumn to the original host
plant may be followed by two or three generations of
asexual, agamic individuals. After that, a short time prior
to the end of the breeding season, the sexual forms are
produced. The appearance of the sexual forms may possibly
be induced (or precipitated) by the ripening and hardening
of the plant tissue of the host. The same factor, in case of
the summer annual host plant, may determine the time of
the return migration to the spring and autumn host plant.

The sexual forms are often wingless and very small and
are less dependent upon the host plant for food than are
the other forms. After mating, the female produces one or
two eggs or at least a very small number of eggs and these
eggs are usually attached to permanent parts of the tree,
seldom to leaves or stems. These eggs are usually hard,

120 ORDER n EMITTER A

tough, usually black, i)(>lishe(l and resistant to the weather.
They are sometimes so abundant on the surface of apple
twigs as to give the latter a shiny appearance. The follow-
ing spring these eggs hatch into the stem-mothers.

Control. — Control measures in general resolve themselves
into destruction of the over-wintering eggs, prompt appli-
cation of insecticides in early spring, and such measures as
are applicable through recognition of the alternate-host
habit. The hop-plant louse control depends on elimination
of the alternate host, wild plum.

To the general and usual method of hibernation in the
egg stage there are exceptions. Thus the corn-root louse
is carried over the w^inter on roots in the ground by its
attendant ant. Through this dependence on the ant being
long-continued this species has evidently become independent
of the egg-depositing habit or produces eggs only at intervals.

Outbreaks of plant lice are often very destructive and
and are more or less evanescent. The lice appear suddenly,
to all appearances, and often seem to disappear as quickly.
The aphids are victims to a multitude of predaceous enemies
and Hymenopterous parasites, are susceptible to weather
conditions, such as rains, low temperatures, etc.

Migrations in spring are usually for short distances, rarely
over a mile or so, or until a suitable summer host is found.
Fall migrations, involving many more individuals, are much
more general and the insects more widely scattered, and are
carried along by wdnds and may be quite widely distributed
at that time. x\mong the important species are the corn-
root louse, hop-plant louse, cherry aphis, apple aphis, etc.

An intimate relationship exists between the plant lice and
ants, this being sometimes carried so far as to make the
insects mutually dependent on each other. Such is the case
with the corn-root louse and its attendant ant, in which the
ant depends for its food upon the honey dew of the aphid
and the latter in turn depends upon the ant for its trans-
jjortation from one root to another. In this and other cases
plant lice are definitely ])rotected by the ants or carried over
from season to season in order that the ants may get the

FAMILY APIIIDJD.E

121

benefit of the lioney dew wliich is extruded from the anal
opening. There is no \er,>' definite glandular struetm-e eon-
nected with the nectar tubes or cornicles but a liquid does
come from them and its function is interpreted in various
ways, one being that it serves the insect in defence against
predaceous or parasitic enemies.

Fig. 74. — Pea aphis (Macrosiphum pisi): a, winged female; b, same
from side, with wings folded in natural position, as when feeding; c, apterous
female; d, nymph in last stage; e, third joint of antenna of winged form;
a and d, much enlarged; e, more highly magnified. (From Chittenden,
Div. Ent., U. S. Dept. Ag.)

The classification of the Aphididse is based largely on the
structure of the winged forms, and it is very desirable that
the winged form of a species be obtained in attempting its
identification.

Other characters of special value are found in the antenna^

122

ORDER HEMIPTERA

relative length and number of joints, location of sensoria
in the honey tubes or nectaries, and the anal style.

Fig. 75. — Spring grain aphis {Toxoptera graminum): male, greatly
enlarged. (From Webster, Div. Ent., U. S. Dept. Ag.)

Pea Aphis. — The pea aphis is a species Avhich occasionally
multiples to an enormous extent and causes heayy losses

Fig. 76. — Spring grain aphis {Toxoptera graminum) : egg-laying female
with eggs in body, greatly enlarged. (From Webster, Div. Ent., U. S.
Dep. Ag.)

in the pea crop. Another yery destructiye species at times
is the one affecting melons.

FAMILY APHIDID.^ 123

Spring Grain Aphis.— The spring grain aphis or "green
bug" (Toxoptem graminum) has attracted a great deal of
attention, especially in the Southwestern wheat growing
sections; in Texas, Oklahoma, and Kansas where it has
caused severe injury to the wheat crop. It is an introduced
species and seems especially adapted to the Southern wheat
districts. It is extensively preyed upon by a small parasite

1

^

1/

SsS ./

'^W?

Fig. 77. — The spring grain aphis {T oxopter a graminum) : winged migrant,
much enlarged; above, antenna of same highly magnified. (After Pergande,
Div. Ent.. U. S. Dept. Ag.)

(Lysiphebus) , and this parasite assists in a large degree in
keeping it in check.

Corn-leaf Aphis. — The corn-leaf aphis {Aphis maidis) is
injurious to the corn plant and occasionally appears in
destructive numbers but ordinarily is less injurious than the
related corn-root aphis.

Corn-root Aphis {Aphis maidi-radicis) . — The corn-root
aphis is a special pest of cornfields and a larger part of its
attack is confined to this crop. It is a light green or bluish-

124

ORDER HEMIPTBRA

green, affected evidently by its subterranean ha})it. The
species is notable on account of its dei)endence on the ant
for its transfer from one foofl })lant to another.

Fig. 78. — The corn-leaf aphis (Aphis maidis): winged female. Much
enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.)

ro. — The corn-leaf aphis {Apld.'i maidis) : wingless female. Mi
enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.)

The eggs of this species are cared for by the ant through
the winter time. When hatched the young are transferred
to suitable \)\nnX roots, often to the roots of weeds in the

FAMILY APII1DID.E

125

Fig. so. — The corn-root aphis (Aphis maidi-radicis) : winged female.
Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.)

Fig. 81 Fig. 82

Fig. 81. — The corn-root aphis (ApJds muidi-radicLs) : wingless female.
Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.)
Fig. 82. — Aphis on apple. (Photo from Ohio Exp. Sta.)

126

ORDER HEMIPTERA

fields, upon which the lice maintain themselves until corn
plants are available

This species appears to become so completely adapted
for underground life and the association with ants that it
does not necessitate producing any winged generation for
distribution or for alternation with another food plant.

On account of this relation to ants, one of the measures
of control is to plow and harrow the ground thoroughly

Fig. 83. — Woolly aphis {Schizoneura lanigera): a, agamic female; b,
larval louse; c, pupa; d, winged female with enlarged antenna above;
all greatly enlarged and with waxy excretion removed. (From Marlatt,
Div. Ent., U. S. Dept. Ag.)

in order to break up the nests of the ants. This method
adopted in the autumn together with a wider cultivation
and destruction of weeds in the fields in spring will assist
in keeping the pest in check. Perhaps the most important
measure is a rotation of crops so that corn will not be culti-
\ated for a number of years in succession on the same ground.
Woolly Apple Aphis {Schizoneura lanigera). — The woolly
apple aphis is a very destructive species, its injury for the

FAMILY APHIDIDAi 127

most part being noted upon apple trees and is credited with
attacks both on the roots and trunks of some trees, limbs
or larger twigs near the ground. It is covered with a white
cottony substance and this tends to shed water. On the

Fig. 84. — Woolly aphis (Schizoneura lanigera) : a, root of young tree
illustrating deformation; b, section of root with aphides clustered over
it; c, root louse, female — a and h, natural size; c, much enlarged. (From
Marlatt, Div. Ent., Circ. 20, 2d series, U. S. Dept. Ag.)

roots it produces large knotty swellings and these injuries
cause serious effects upon the tree. Usually these insects
are observed in a wingless form but in the autumn some of
the individuals become winged and migrate to the elm,

128

ORDER HEMIPTERA

where in tlie spring of the following season they produce
rosette galls, later migrating back to the apple. The rosette
gall has been separated from the leaf curl gall produced by
Schizoneura americana, a species that is a frequent pest on
elm trees.

1

Fig. So. — \\'<)olly aphis on apple twigs. (Photo from Ohio Exp. Sta.)

Remedies for the root form are difficult, but for orchard
trees after removal of the earth, sprinkle tobacco dust on
the roots and replace the soil. The use of 10 per cent,
kerosene emulsion can also be recommended. Above ground

FAMILY ALEYRODID.E 129

the use of tobacco extract or 7 per cent, kerosene emulsion
may be used.

In another group of aphids we have the gall-makhig
pemphiginse which cause conspicuous deformations upon the
leaves of many different plants. Some of the more con-
spicuous ones are the vagabond gall on cottonwood, and the
poplar leaf galls.

Grape Phylloxera. — The Grape Phylloxera is one of the
very destructive insects of the grape-vine and is known over
a wide territory, having been carried from America to Europe,
where it caused a great deal of destruction to the vineyards,
especially in southern France. It affects the roots of the
vines and occurs on these during autumn, winter and early
spring, but during midsummer migrates to the leaves, caus-
ing the production of leaf galls, so conspicuous at that time.
By the time these galls mature or the leaves ripen the insect
migrates to the roots. The use of bisulphide of carbon
injected into the soil is the most available remedy, but there
is so much difference in the resistance of different varieties
of grape that the cultivation of thick-leaved kinds is con-
sidered advantageous. Where flooding is practicable, the
submergence of the insects for a period of two or three days
is effective.

Numerous species of phylloxera occur on the leaves of
hickory, walnut, and other trees, but for the most part are
not considered of especial economic importance.

Family Aleyrodidse — The next family in the series is the
AleyrodidoB. These are forms which have a mealy covering
on the wings and have the eyes divided, each compound
eye being divided into two, and the antennae being located
within the division of the eye. The adults are very similar
but the larvae and nymphs which form scale-like bodies on
trees have very distinct characteristics so that the species
are to be distinguished by the study of these stages rather
than of the adults. They resemble somewhat the scale in-
sects, but the adult characteristics are quite different. The
scales are quite distincti^'e. In many cases there is a fringe
of white, waxy material which seems to act as an attach-

]:!() ORDER HEMIPTERA

ment to the surface of the bark. • This often lifts the scale
from the surface of the bark. There are distinct differences
in the markings of the body and in the anal plates. A rather
destructive form occurs on greenhouse plants, and is known
commonly by the name of "white fly." In some instances
it is very destructive. The eggs of the adults are laid on the
leaves and the larva? fix themsehes after a short migration
and develop until they have reached the pupal stage, and
from this stage the adult winged form issues. The family
is not so large nor so important as the scale insects — Coccidoe.
Two species occur on oranges in Florida; one, the orange
white fly, is often the means of serious loss in orange orchards.
They are treated by sprays and by culti\'ation of certain
parasitic fungi.

COCCID^.

The Coccidoe, scale insects, or bark lice, are to be considered
as the extreme branch along the line of specialization found
in this group. There are se^•eral subdiN'isions with various
kinds of specializations. The group is characterized by the
absence of wings in the females and the reduction of wings
in the males to one pair, they are usually firmly attached
to the plant on which the larva has settled and even in
forms not attached probable means of migration are limited.
The males are winged but show distinct specialization in
the reduction of the second pair of wings. These constitute
simple, aborted, hook-like structures that can serve no pur-
l)ose in flight. The same kind of reduction as in Diptera.
'Jlie males also show a fairly distinct metamorphosis. The
larvse change to a quiescent pupal stage and this gi\es rise
to an adult two-winged male. The females are wingless
and usually immo^'able, mating depends entirely upon the
migration and flight of the males.

Owing to the extent and the economic importance of this
grou]), it seems desirable to give some account of the sub-
families and to discuss somewhat in detail certain of the
especially important economic species. Their sedentary
habits permit a ready distribution, yet make it easy to

COCCIDM

131

control them by proper laws for exclusion. In determina-
tion, the appearance and color of the scale and the appear-
ance it gives to the trees are very important. There are
several subfamilies but the following include the x\merican
species of importance.

The Dactylopiincp, including the mealy bugs and related
forms, differs from other members of the family largely in
the fact that the species are less fixed in habit. The mealy

Fig. 86. — Orlhczia aolidaginis Sanders on goldenrod leaves,
author.)

(Photo by

bugs are particularly active and capable of traveling about
readily. They are covered with a whitish, mealy secretion
.from which they derive their name, and in temperate regions
are found for the most part in greenhouses but there are a
few native outdoor species. The common mealy bug of
greenhouses (Pseiulococcvs citri) is a very well-known pest
and may be found in different stages of its life history in
almost any greenhouse and frequently upon house plants
if kept where there is moisture. Fumigation and the use of
washes are available for their control.

132

ORDER HEMIPTERA

An interesting subdivision of the group includes the
Ortheziince which secrete a white calcareous secretion which
appears in plates or filaments extending from the body, often
as long parallel bars extending back some distance from the
body. A rather common species in the Northern States is
solidaginis , occurring on goldenrod. There also is included
in this group the very destructive cottony cushion scale,
Icerya purchasi, which for a time threatened the fruit

Fig. 87. ^Pulvinaria innumerabilis: adult females in position on twigs
with egg sacs — natural size. (Howard, Div. Ent., U. S. Dept. Ag.)

industry of California but which was brought under control
by the importation of the Australian lady bird {VedaVia
cardinalis).

The subfamily Coccincp includes what are termed the soft
scales. The bodies of these are covered more or less com-
pletely with a waxy secretion which adheres firmly to the
body wall and furnishes a thick, more or less rigid protec-
tion to the body. Most of them adhere fixedly to the bark
or leaves but in some cases a migration at the time of moult-

COCCID^

133

ing or when changing from the nymph to the adult stages
may occur.

Maple Scale {Puhinaria innumerahilis). — The maple scale
is a wide-spread and occasionally abundant and destructive
species, attacking particularly the soft maple and occurring
at times on other trees or woody plants. In this species
the adults mature in autumn and winged males issue from
the scale and mate with the females, the latter remaining

Fig. 88. — Puhinaria innumerahilis: a, newly hatched young; h, female,
third stage, from above; c, same, from side; d, male, thiid degree; e, same,
natural size, on leaf and petiole; /, same, enlarged, on leaf petiole showing
two specimens parasitized, all greatly enlarged except e. (From Howard,
Buieau of Entomology, U. S. Dept. of Agriculture.)

unwinged. They may, however, migrate from leaves to
twigs or branches and attach themselves firmly for the
winter, which is passed by the adult female only. In spring
the eggs are developed and by early June a very large cottony
mass is formed beneath the scale, lifting it from the bark,
except at the anterior end, and within this large cottony
mass an enormous number of eggs are deposited. Hatching
of the eggs occurs shortly after the deposition and the larvae

134 ORDER HEMIPTERA

travel rapidly for a day or two, going especially toward the
outer and upper branches where they fix themselves, and
during successive moults remain attached to leaf or bark
until autumn, when the adults mature, completing the life-
cycle.

Diaspinae. — The armored scales (Diasplmp) differ from
the preceding forms in that the waxy secretion separates
from the body wall and forms an external shield or cover
within which the scale insect is enclosed and within which
there is some possibility of movements of parts, although
the mouth parts are anchored quite permanently in the
bark. Classification of the species in this division is com-
plicated by the presence of this external scale, although in
many species the external features of the scale are a fairly
good basis for the recognition of the species.

A microscopic examination is required to determine the
species in many cases. The pygidium (the fused terminal
segments of the abdomen of the female) includes the char-
acters most often used, as it is highly chitinous so that it
holds its peculiar characters even after a long time in a
dried state. Specimens kept dry twenty to thirty years
may be used for examination. The dorsal surface may have
glands that produce waxy secretion forming the scales. The
anal opening is also on the dorsal side.

Upon the ventral surface the vaginal opening is a con-
spicuous landmark and ordinarily grouped around this are
small spinnerets which appear under the microscope as
strongly chitinized circles. There are generally- four or five
groups. These groups are named according to their relation
to the vaginal opening. The median or anterior group is in
front of the vaginal opening and on each side at about equal
distances are the cephalolateral or anterolateral group and
the caudolateral group. These spinnerets or grouped glands
are entirely wanting in the San Jos6 scale.

The marginal structure of the pygidium takes second
place in the determination of species and the number and
shape and modification of the lobes are very important.
In some cases there are thickenings of the margin that closely

COCCIDM 135

resemble the lobes. The incision of the margin by their
shape and extent afford characteristics of value.

Spines on the lobes are commonly present and aft'ord quite
serviceable characters. There are generally two for each
lobe — one on each of the dorsal and ventral surfaces. In some
cases these spines are tubular and threads may sometimes
be seen issuing from them.

The plates are distinctly modifieil spines. They are gf^n-
erally flattened and frequently notched. The simi)le forms
differ from spines in that they do not have a globular base.
Wax ducts a])i)ear as hairs on spines which extend into the
body.

Chionaspis Salicis. — The willow scale {Chiomispis salicis)
possesses a, dense waxy structure overlying and separate
from the body of the insect. The mouth parts are imbedded
in the bark and saj) wood. The head is pretty well marked
but antenupe and legs are reduced. There are two entirely
different kinds of scales on the willow. The larger is an oval,
somewhat elongated scale, the smaller narrow and with
three rather fine ridges. The large scale is the female, the
smaller the male. The growth of scales takes place during
summer months; they increase in size by successive moults.
As the larval scale is shed it is left attached to the new scale,
and so on, often two or three are attached to the outer sur-
face of the scale. By autumn these will have reached
maturity, and mating will occur prol)ai)ly by early October.
The males all die off" immediately and the females deposit
eggs and then shrivel u}) and die before winter. The female
never leaves the scale at all.

At the beginning of winter there is tiiis mass of eggs
protected under a scale as the means of carrying the insect
over to the spring. They hatch probably during early Jime,
possibly the latter part of May. Eggs are reddish-purple.
The larvffi crawl from under the scale and scatter out and
make a special effort it would seem to get on new twigs and
fresh growth of wood. They seem to travel upward in the
lightest direction and this naturally carries them out to the
ends of the twigs and leaves. Diu-ing this migration period,

136 ORDER HEMIPTERA

which lasts two or three days, they may be distributed in
several ways. A good breeze might carry them some little
distance. They may be carried by birds. They may be
carried on pieces of plant on which they occur, which is the
means hx which most of the scale insects are distributed.

Fig. 89. — Chionaftpis furfurus. Scurfy scale on apple. (Photo from Ohi<
Exp. Sta.)

Oyster-shell scale is named from the shape of its scale.
It is a European species, but occurs as a widely djistrib-
uted species in this country and affects a number of host
plants, principally the apple. The adults mature in fall and
white eggs are deposited mider scales and survive the winter,
hatching early in June. The larvae then scatter and develop
during the summer.

COCCIDM 137

San Jose Scale.— The San Jose scale is an introduced
species which has been the source of an immense amount of
loss in orchards, nurseries, etc. It presents some modifica-
tions from the ordinary forms. It is small with an almost
perfectly circular scale. The exuviae remain near the centre,
giving it a somewhat nipple-shaped appearance. When

Fig. 90. — San Jose scale; male adult — greatly enlarged. (After
Howard.)

abundant they give a very scurfy incrusted appearance to
the twig on which they occur. The male scales are smaller
.and a little more oval in shape. The life history differs from
most other species in that young are produced alive, the
eggs hatching before extrusion, and the young develop
rapidly, mature in a short time, and produce another genera-
tion. There may be as high as four to six generations in a

138

ORDER IIEMIPTERA

season. It has been estimated that a single female may be
the parent of about three and a half billions in a single
season. Since there is no egg, but young are brought forth
alive, they must ha\^e constant nutrition, and unless the scale
is attached to living tissue the insects must perish, except

/

\

" -.„[.,.■

x-

c

Fig. 91. — San Jose scale: c, adult female containing young — greatly
enlarged; d, anal fringe of same — still more enlarged. (After Howard.)

that mature females may assume a dormant condition dur-
ing cold weather. The only means of transportation to
distant points, therefore, appears to be upon living plant
tissue, and this makes it possible to prevent its distribution
by adopting restrictive measures through inspection and
quarantine.

COCCIDM

139

For measures of treatment where exclusion is not possible,
there are two or three fairly effective remedies in the killing
of the scale. One of these is kerosene emulsion, made by
agitating kerosene and soapsuds. One gallon of water,

Fig. 92. — San Jose scale on leaves aiul fruit. (Photo from Ohio Exp. Sta.)

one-half pound of soap brought to the boiling point and then
mixed (away from the fire) with two gallons of kerosene
and then agitated into an emulsion by a force-pump or egg-
beater. This is diluted with soft water, one part of emul-
sion to eight or nine parts of water.

140 ORDER HEMIPTERA

Whale-oil soap is sometimes used, but the most favored
remedy at the present time is lime-sulphur wash formed by
boiling the ingredients together. This is applied by means
of a spray-pump so that it covers the trees. If these appli-
cations are made thoroughly the scales may be killed off to
a great extent, though it is is hard to completely exterminate
them. Badly infested trees will seldom recover and it is
about as well to cut out and destroy such trees. Remedies
that can be applied when larvae are travelling will be more
effective, but in San Jose scale larvse are travelling most of
the summer months. In those species where there is a

Fig. 93. — Peach orchaid mjurod 1)\ Pan .lose tcale Nogleotcd, badly
infested orchard at right and injured rows adjacent in spite of careful
spraying with protection to rest of orchard at left. (Photo by author.)

definite period for the larvae, spraying even with clear water
if the pressure is great will reduce their numbers considerably.
It is important to know the life histories perfectly.

The Heteroptera include those forms which have wings
thickened at the apex and in which the mouth parts arise
from the most anterior portion of the head, and both in this
character and in the wing structure are evidently more
specialized than the Homoptera. It is not possible to say
that any of the Heteroptera present more specialization in
certain lines than some of the Homoptera.
[_ The families are pretty well marked, and a number of

com SI DM 141

the groups are aquatic, a number terrestrial, and some
arboreal. The aquatic forms are derived from the terres-
trial. Most of them are obliged to come to the surface of
the water to secure air at various intervals and this shows
that they are modified from terrestrial forms. The aquatic
forms pass the larval stage in the aquatic life but in most of
the aquatic families the adults are also aquatic, though they
may issue from the water and fly readily out of water. The
eggs of aquatic forms are deposited on aquatic plants dis-
tributed in the water and only in a few cases do they show
marked peculiarities in the matter of egg deposition. In
one of our common species, the smaller water bug (Zaitha
fluminea), the eggs are deposited on the back of the male

c b a

Fig. 94. — Water bugs: a, water boatman, Corisa harrisii; b, Notonecta

irrorata; c, Notonecta undulata. Enlarged X 1.42. (Photo by C. J. Drake.)

by the female in a rather large mass, the eggs being set on
end attached to the wing covers and are carried in this way
for some time until they hatch.

Of the terrestrial forms there are a considerable number of
families. Some important species, chinch bug, squash bug,
etc. The effect of the chinch bug on cereal crops is very
damaging.

Water Boatmen {Corisidcp). — The water boatmen are small
species. Their legs are modified for swimming, the hind
ones being long, wide, and oar-like, having a series of cilia
which aid much in swimming. The species are found in large
numbers in ponds and streams, occasionally they fly in large
swarms. Spring is the usual time when they are seen flying

142 ORDER HEM I FT ERA

and are attracted very much by lights. They constitute a
food supply for fishes and they themselves feed on other
aquatic organisms. One s})ecies in Mexico is dried and used
for food by the natives and is also sold in the markets as
bird food. There is some question as to their economic
importance.

Notonectidse.^ — These are generally larger than the Corisidce.
The striking thing about them is that they swim back down-
ward, coming to the surface of the water at intervals for air.
Our common species is Notonecta undulata. This species
has a severe bite and it is best to handle it w4th care.

Water Scorpions {Neyidoe). — The water scorpions are
characterized by a long respiratory tube at the end of the
body; a very much elongated coxa in the forelegs so that
the femur and tibia can be thrust out from the end of the
body to catch prey. They are generally found in shallow
water, secreted in dead leaves close to the bottom. How-
ever, they are strictly dependent on air for respiration and
get it by sticking this respiratory tube up to the surface of
the water. They are strictly carnivorous, puncturing their
prey and sucking the blood. If they are touched they feint
and their legs may be broken off without any motion on
their part.

Belostomidse. — These are the giant water bugs and are the
largest bugs belonging to this order. They have a short
respiratory tube and a strong and somewhat curved beak;
and can inflict a very severe bite. They are quite preda-
ceous, feeding on young fish, and sometimes even those
larger than themselves. Thus they are of distinct impor-
tance as destroyers of fish. They go through all the stages
of their life-cycle below the surface of the water. The eggs
are laid under water on the stems of plants or in the case
of one species on the back of the insect itself. The eggs
are cemented so tightly that sometimes the shells remain
long after the eggs are hatched. The young at first are
nearly the form of the adults but without wings. They
grow by successive moults and with gradual appearance of
wing pads until they reach the adult stage.

BELOSTOMID/E

143

Two species, one found in the Philippines and the other
in South America, are much larger than those found here.

Fig. 95. — Water scorpion {Ranntrn amcricana). (Drawn by Jos. D. Smith.)

144

ORDER HEMIPTERA

There are two large species commonly found in the United
States, the Belestoma amcricana, which has a groove along
the inner margin of the forefemur, while the Benacus griseus
has none. The latter is also slightly larger, has the hind
tibiae broader and the legs not so distinctly annulated with
dark rings.

Fig. 96. — Giant water bug (Benacus griseus Say) : dorsal and ventral
views. Slightly enlarged. (Original photo by C. J. Drake.)

Water Striders (Ilydrohatidcp). — This is a very interesting
group. Their bodies are covered with a ^'ery fine velvety
coat which sheds water, thus enabling them to live on the
surface of water. They look somewhat like spiders, the
legs are long and extend outward in a spider-like manner.
The front pair are shorter than the others, being used to
catch food. The antennae are short and are hard to dis-
tinguish from the first pair of legs. Along with these forms

REDUVIID^ 145

there are several little shore-living species, of no economic
importance, however.

Predaceous Bugs. — The Assassin Bugs (ReduviidcB).—
The assassin bugs are rather large-sized insects with slender
bodies and legs. The beak is rather strong and short and

Fig. 97. — Water stridor {Limnogonus hcsione). (Drawn by Jos. D. Smith.)

is fitted for puncturing insects. The species generally are
predaceous, feeding very largely on destructive insects.
Several species, however, puncture warm-blooded animals
and suck their blood. The most familiar one of this kind
is the " kissing-bug" or blood-sucking cone-nose. This
is a strictly Southern species and is rarely found north of
10

146

ORDER HE MI PT ERA

of the Ohio River. It occurs in the Southern States and
occasionally in Ohio. The masked bed-bug hunter is com-

FiG. 98. — Blood-sucking cone-nose {Conorthinua sanguisugus) : h, nymph;
c, adult. Enlarged. (From BuJ. Ent., U. S. Dept. Ag.)

Fig. 99. — The "kissing-bug" or masked bed-bug hunter {Redurius perso-
notus). (After Howard, Div. Ent., U. S. Dept. Ag.)

mon in both Europe and America. The wheel bug, so-called
on account of the round thorax, is also found in the South.

ACANTHI D^

147

The tliread-legged bug is a very thin insect which, Hke
the water scorpion and praying mantis, has the coxa of the
front legs elongated for grasping. The damsel bugs {Nahidce)
are serviceable in eating leaf hoppers and like pests. While
the ambush bugs {Phymaiidcp) are serviceable in reducing
the number of destructi^•e insects, they also show protective
coloration to a marked extent. Phymata erusa is our common
species. It is commonly found in blossoms of goldenrod or
other plants where it catches insects which visit the flowers.

The Bed-bug Family {Acanthidce). — These bugs are much
flattened and are pretty generally predaceous or blood-
sucking. The most common species, bed-bug {Cimex lectu-

¥iG. 100. — Phymata erosa: a, dorsal view; h, lateral view; c, front leg;
d, snout — a, h, enlarged; c, d, more enlarged. (Riley, Div. Ent., U. S.
Dept. Ag.)

larivs), is restricted to houses and is quite largely dependent
upon human blood for food. It is almost entirely wingless,
the wings being very small, owing to disuse, and thus becom-
ing entirely useless as organs of flight. This species is
distinctly averse to light and hides during the daytime in
cracks and crevices, coming out at night to feed. They are
light colored when young and become darker with growth,
and appear darkest just after a meal, which consists of blood.
The feeding periods are far apart and the species is able to
live for a long period without any supply of food. It is said
that one can live a year without food. They cannot crawl,
and depend upon being carried from place to place on cloth-
ing. They are commonly found in cheap hotels and board-

148

ORDER HEMIPTERA

ing houses and when once estabhshed in a place it is very
difficult to get rid of them. The life history of the species
is not very definitely known.

The eggs, which are deposited upon furniture and in cracks
and crevices, are white and rather long and cylindrical.
They hatch in a few days, the yovnig are of the same shape
as the adult but are white. The young bugs moult five or
six times before they are mature. The growth is very slow

Fig. 101. — The bed-bug {Cimcx lectularius): a, adult female gorged with
blood; b, the same from below; c, rudimentary wing pad; d, mouth parts.
a and b much enlarged; c and d, highly magnified. (Marlatt.) Relapsing
fever and kala azar are carried by the bed-bug. (Rosenau.)

and irregular, all depending upon opportunities offered for
getting food. This species does not have a regular life-cycle
as insects which live out of doors under the influence of the
seasons. Bed-bugs can be killed with sufficient effort, cor-
rosive sublimate being one of the best remedies. Kerosene,
gasoline, or hot water prove very effective. Constant
attention to furniture and the destruction of those bugs
which appear is the most essential thing in their destruction.
Bed-bugs are of considerable importance from the fact that

CAPSIDJS

149

Fig. 102. — Coquilletia mimetica Osborn: a, female dorsal view; h, female,
ventral view; c, female lateral view; d, male ventral view; e, male dorsal
view; /, larva; g, female abdomen enlarged; h, male abdomen enlarged.
(After Osborn. From drawings by Miss King.)

150

ORDER HEMIPTERA

they have the power of transmitting blood diseases from
one person to another.

The Tingitidoe, or lace bugs, are common on thorn bushes,
sycamore, oak, walnut, and many other plants.

The leaf bugs (Capsidce) are of some economic importance,
from the fact that the^' attack the leaves of fruit trees in

Fig. 103. — Sericophancs ocdlalus Rent: dorsal \io\\-~ a, iiKU'iopterous
male; ?), micropterous female; c, macropterous female, f/, -^ulo mow microp-
terous female; e, macropterous female; /, wing of nucropteious female; a,
micropterous female; h, male abdomen beneath. (After Osborn. Drawn
by Miss C. M. King.)

the spring, puncturing them and sucking the plant juices.
They are also quite common in meadows and pastures.

The tarnished plant bug is a very important species
affecting orchards where it attacks the buds and blights
them. It also works on clover and does great damage to
strawberries, causing "buttoning."

Certain species in this family show a ^'ery strict resem-

LYGAEIDM 151

blance to ants, and this is especially so in the case of the
species of Pilophorus, Coquilletia, and Sericophancs.

One of these species, Coquilletia mimetica, carries this
resemblance to the extreme in the development of small
elevations on the first and second abdominal segments
which correspond closely to the first abdominal segment of
the ant. The female in one form is entirely wingless, biit a
full-winged form of female also occurs, and the males are
full-winged. '

Another species, Sericophanes ocellatns, shows somewhat
less modification in that the wings are not completely lost

104. — Chinch bug (Bht,su^ hucopttnt^) . adult of loiiK-wiiiged form,
much enlarged. (From Web'iter, Div Ent., U. R. Dept.. Ag.)

but are retained as short rudiments which extend over
the basal segments of the abdomen. The efl'ect as a whole,
however, closely simulates the appearance of an ant.

The family Lygaeidse includes the chinch bug and numer-
ous other small bugs, but few of which are of economic
importance.

Chinch Bug (Blissus I eucoptenis).— The chinch bug is very
important as a farm pest. It has a long, slender body with
parallel sides and four-jointed antennte. The body is black
and the wings white. It occurs all over the Mississippi
Vallev and south to Central America but it is most serious

152

ORDER HEMIPTERA

in Illinois, Missouri, Kansas, Nebraska, Iowa, and parts of
Indiana, and occasionally in parts of Ohio. The losses due

%>?

Fig. 105. — Chinch bug: a, b, eggs; c, newly hatched larva or nymph;
d. its tarsus; c, larva after first moult; /, same after second moult; g, last-
stage larva; the natural sizes indicated at sides; h, enlarged leg of perfect
bug; j, tarsus of same, still more enlarged; i, proboscis or beak, enlarged.
(From Riley.)

to this insect are large, being estimated as high as $60,000,000
and amounting to $20,000,000 in one State alone in one year.

Fig. lOG.— Chinch bug. Adults of short-winged form, much enlaigcd.
(After Webster, Bur. Ent., U. S. Dept. Ag.)

It has two generations a year and the winter is spent in
the adult stage under bark of trees, bunches of grass, fence
corners, etc. Often if a thicket is near they will migrate

LYGAEID^

153

to it. In the prairies they hide in the grass and emerge in
the spring. The female begins to deposit eggs in April and
May. This is done gradually and extends over a period of
about three weeks. This early deposition is usually done
about one-half inch under the ground on the stems of spring
or winter wheat. The eggs are white and very minute and
ha\'e four little projections at the head end. They hatch
in three or four days after deposition, into minute little

Fig. 107.— Chinch bug on corn. (Photo from Ohio Exp. Sta.)

white bugs with small red spots, having the same shape as
the adult but lacking in wings. They are unable to feed on
plants outside of the grass family, migrate to corn after the
wheat is cut and while some ha\'e wings fully developed they
usually all move on foot. At this time they can be easily
killed. The eggs of the second brood are laid on the corn
stalks. Before cold weather comes there is an extensive
migration, probably accompanied by mating, and the insects
hibernate. One group matures in the summer and dies while

154 ORDER HE MI PT ERA

the second group matures aufl hibernates and produces a
spring brood.

The control of the cliinch bug is based on the use of barriers
between the wheat fields and the corn, and a dust furrow
is good, or the placing of n cro]) that they will not feed on,

^^S '' ^^WBup

\^^^|^^^^^^W

%M

I'Ui. lOS.— C'lun.-h l.uu. (Phot.)inicn.^rai.li from Oliio Kxp. 8ta )

such as potatoes, between the corn and wheat. When the
bugs first go into the corn they stop on the first few rows
and when there they may be killed with kerosene emulsion.
Rotation of crops is a good thing and the burning of waste
grass and weeds in the late fall gets those that li%'e there.

COREIDM

155

They may be ploughed under in the stubble but this must
be at least five inches deep. The introduction of a fungus
which was fatal to the bug was tried extensively but without
success sufficient to warrant its recommendation as a reliable
measure of control.

Family Coreidse. — This family includes the squash bug
and a number of other prominent species. They are dis-
tinguished by the robust body, numerous veinlets in the
membrane and the four-jointed antennje. The common

.

^^-

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Hil)ern:itiiiii quartors. (Photo from Ohi
Exp. 8ta.)

squash bug is a very familiar species, a large dark colored
insect about three-fourths of an inch long. It hibernates
in adult form secreted around buildings or under debris on
the surface of the ground and in early summer deposits eggs
on squash or melon vines. The nymphs puncture the leaves,
and their attack upon the plant often results in a complete
withering, so that if the insect is numerous the crop may be
seriously affected. The eggs are small glistening objects
attached in loose clusters upon the under side of the leaf.

156

ORDER HEMIPTERA

The nymphs are at first without trace of wing pads, but in
successive instars the wing pads increase in size. The
different instars are shown in the accompanying figure.

Fig. 110. — Anasa Iristis: a, mature female; b, side view of head, show-
ing haustellum; c, abdominal segments of male; d, same of female; a,
twice natural size; b, c, d, slightly more enlarged. (From Chittenden,
Div. Ent., U. S. Dcpt. Ag.)

Fig. 111. — Anasa trislis nymphs: a, newly hatched; b, second stage; c,
third stage; d, fourth stage; e, fifth stage — all about twice natural size.
(From Chittenden, Div. Ent., U. S. Dept. Ag )

Box Elder Bug (Leptocoris trivittatus) . — The box elder bug
is black with red lines, and since this species has been migrat-

COREID^

157

ing eastward from an original westward habitat it is of
interest to note its progress. In recent years it has been
observed as far east as Ohio and it is quite Hkely to extend

Fig. 112.— Eggs of Anasa tristis: a, from below, showing point of attach-
ment; b, from side, showing place of escape of nymph; c, sculpture of egg;
d, egg cluster; a, b, about five times natural size; d, onp-fourth enlarged;
c, greatly enlarged. (From Chittenden, Div. Ent., U. S. Dept. Ag.)

Fig. 113. — Leptocoris triviltalus: a, eggs enlarged, natural size above,
b, c, d, different stages of immature bugs; e, adult; all enlarged; natural
sizes indicated by hair lines. (All after Marlatt except e, which is after
Howard, Div. Ent., U. S. Dept. Ag.)

158

ORDER HEMIPTERA

its range to the Atlantic coast. It attacks particularly box
elder trees and the young probably feed upon this in prefer-
ence to other plants, but the adults in autumn scatter quite
widely and in some instances are quite troublesome in

Via. 114. — Coruuii crastiicornis. (After Hainljleton.)

houses because of their tendency to fall into all kinds of
objects such as milk pans and other food receptacles.

The species of Corizus are small, robust forms occurring
on a very great \'ariet\' of plants and commonly noted along
roadsides and in clover fields.

PENTATOMID.E

159

Stink Bugs {Pentatomidce). — Stink bugs are rather broad
oval-shaped insects with four- or five-jointed antennte, the
wings lie flat and the membranous tip of the second pair
are uncovered. They have a rather large scutellum lying
between the bases of the wings. The characteristic odor of
the stink bugs is not confined to this particular family. A few
members of this family are of economic importance. The
green soldier bug is very destructive to peaches in the northern
part of the United States. The spined soldier bug {Podisus

Fig. 115. — The spined soldier bug (Podisus maculiventris) : adult at left,
nymph at right; much enlarged. (Chittenden, Div. Ent., U. S. Dept. Ag.)

inacuJivcvfris) is not very large and is characterized by very
distinct spines which project from the side of the body.
It is very distinctly a predaceous bug. It is credited with
killing the larvae of the Colorado potato beetle, and it also
feeds on caterpillars and other insects. On the whole it is
counted as being very beneficial.

Tlie harlequin cabbage bug (Murgantia histrionira) is
one of the species common in the Southern States, and if it
becomes abundant is a very serious pest. Ohio is its northern

160

ORDER HEMIPTERA

limit. It can be controlled by spraying with kerosene emul-
sion during the larval stage.

The subdivision Parasita includes the suctorial lice, and
they present perhaps the greatest divergence from the
normal form, the extreme being in the direction of reduction
due to parasitism. They are entirely wingless; they have
a reduction of the mouth parts which is extreme. The beak

Fig. 116, — Stink bug: a, adult; b, eggs attached to leaves; c, d, e, f,
details of egg structure. (Bur. Ent. U. S. Dept. Ag.)

is reduced to a single segment through which the tubular
setse are projected — a derivation from the three- or four-
jointed beak of the normal forms. There is a distinct
reduction or retrogression in the wings and mouth parts,
but a distinct specialization in the structures by which
they clasp the hairs or feathers of host forms. Tarsal claws
are very large and strong and are provided with ridges or
roughened areas which seem to strengthen the hold upon

PARASITA 161

the hairs, and in a few forms there are still other speciaHzed
clasping structures to strengthen this hold. In some the
antennse serve to help hold on. In one form there is a
tubercle developed so that it fits against the pair of legs
next forward so that it seems to act as a clasping organ.
These suctorial lice are limited to mammals for their hosts.
The mouth parts are doubtless adapted to the reaching of
the capillary blood system in these hosts and in their life
history they show adaptation to the parasitic habit, the eggs
being glued to the hairs, the larvae on first hatching being
capable of attaching themsehes to the hairs so that the
entire life-cycle is distinctly parasitic. Their migrations
from these host forms are simply for the purpose of scatter-
ing to other individuals of the same species. There is a
rather distinct tendency for the individuals to migrate to
younger animals of the same species. There is not a very
evident series of broods in a year — they probably breed
rather promiscuously. They have a constant host and
constant warmth. Three species affect man and the horse,
ox, sheep, hog, dog, and a great number of other mammals
are known to support one or more species.

Short-nosed Ox Louse (HoBmatojnmis eiirysternns Niizsch).
— The short-nosed ox louse is the common species occurring
on cattle. The full-grown females are about one-eighth
to one-fifth of an inch long, and fully that in width, while
the males are a little smaller and proportionately a little
narrower. Aside from the difference in size the sexes differ
very decidedly in the markings and structural features upon
the under side of the body. The female is bluish leaden or
gray in color. The males have a broad black stripe rlmning
forward from the end of the body to near the middle of the
abdomen, as shown in Fig. 117. The females have no
indications of this stripe, but the black, broken band of the
upper side of the terminal segment extends slightly around
on the under side. The most important character, however,
is the presence of two little brush-like organs on the next
to the last segment, as shown in Fig. 117.

The head is bluntly rounded in front, nearly as broad as
11

162 ORDER HEMIPTERA

long, and with the antennae situated at the sides midway
from the posterior to the anterior borders; behind these
are located slight eminences upon which may be found the
small eyes, which are seen with considerable difficulty. At
the front of the head may be seen the small rostrum or beak,
the end of which is usually near the surface, but which is
capable of extension or retraction. The end of this beak is
armed with a double row of recurved hooks (see Fig. 115).

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Fig. 117. — Hoematopinus eurysternus: a, female; b, rostrum; c, ventral
surface of the last segments of the male; d, same of female; e, egg: /, surface
of same greatly enlarged. (Author's illustration, Bur. Ent., U. S. Dept.

Ag.)

Hog Louse {Iloematopiuus iirius). — The hog louse is one
of the largest species of the family, full-grown individuals
measuring a fourth of an inch or more in length. It is of a
gray color, with the margins of the head and thorax and
most of the abdomen dark. The head is quite long, the
sides nearly parallel, with strong eminences just back of
the antenna^, which are set on the sides of the head, midway
from rostrum to occiput; the legs are lighter, with dark
bands at the joints; the spiracles are inclosed by a black

PARASITA

163

chitinous eminence, and there is a broad black band on the
last segment, broken near the middle. (See Fig. 118.)

The male has the abdomen marked beneath with a large
black area extending forward from the end of the terminal
segment, so as to occupy the central portion of the last
three seg^ments.

Fig. 118. — Hcematopinus urius: a, female; b, ventral view of posterior
segments of male; c, leg, showing protractile disk of tibia — enlarged.
(.•Vuthor's illustration, Bur. Ent., U. S. Dept. Ag.)

A curious provision is found in the feet for strengthening
the hold upon the hair. It consists of a circular pad-like
organ or disk in the outer portion of the tibia, which is
received in a conical cavity in the end of the tibia, and which
can be forced out so as to press upon the hair held between
the claw of the tarsus and the end of the tibia.

164 ORDER HEMIPTERA

On account of the thinness of the hair, the application of
remedies, where necessary, is quite easy. Washes of tobacco
water or dihite carboHc acid, and the appHcation • of kero-
sene in lard, or kerosene emulsion by means of a force pump,
sulphur, ointment, etc., are recommended. The application
of fine dust may be provided for naturally by allowing the
hogs a chance to roll in a roadway or any place well supplied
with fine dust. Where this is impracticable the dust, ashes,
or powdered charcoal may be applied directly to the neck and
back of the infested animal. The species is not known to
attack any other of the domestic animals, and hence no pre-
cautionary measures in this direction are necessary.

CHAPTER VI.

^NEUROPTERA AND ALLIES.

The insects with complete metamorphosis inckide first
the NeuroiAera which are represented by the lace-winged
fly, ant lion, etc. These are separated from the preceding
groups by the fact of the complete metamorphosis, and this
order includes groups which are quite distinct from each
other and have biting mouth parts and rather densely net-
veined wings.

Order NEUROPTERA.

Of the first family Sialidce, the Corydalis cornuta is the
most prominent. The larvse live in running streams and
under stones. Their structure and life-cycle furnish a
good example for the group. The larva is strictly aquatic
with gills which enable it to live in the water, but it can sur-
vive out of water if the gills are moistened. The adults
appear in the summer, mainly in the early part of summer,
and the eggs are laid during the summer months, generally
about midsummer, and deposited in large masses on the
leaves of trees overhanging water. The larvae on hatching
drop at once into the water and begin an aquatic existence.
They feed on the larvse of other aquatic insects, and their
life-cycle occupies three years. They are in the water for
about two years and eleven months; the pupa stage, passed
in muddy banks, as well as the adult stage being short.
The larva changes to a pupa which is quite different from
the larval stage and different also from the adult. They
are counted excellent as fish bait, and this is perha])s their
most direct economic value.

The MantispidcE have very prominent front feet, wings lie
flat over the back and resemble a small form of the mantis.

The family ChrysopidcB, which includes the lace-winged

(165)

166

NEUROPTERA AND ALLIES

flies, has quite a different larval habit, being carnivorous but
not aquatic. Lar\a^ are frequently called the "aphis lions"
as they are destructive to aphids. They are most commonly
found on trees on which aphids are abundant.

Fig. 110. — Corudulis cornuUi. t

Photo Ijy author.)

The adults are very delicate with very thin, transparent,
irridescent wings; brilliant golden eyes which stand out
prominently (therefore called golden eyes) ; wings closely
net- veined and bodies slender and cylindrical. The eggs are

ORDER NEUROPTERA

167

deposited on leaves or twigs and are elevated on stalks,
each egg standing up on a ^'ery distinct thread or pedicle.
This is considered to be for protection of eggs from newly

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168 NEUROPTERA AND ALLIES

hatched lar\'fe of the same colony. The eggs are deposited
in this way by the adult touching the abdomen to the sur-
face of the leaf, then raising it quickly so that a thread of
glutinous secretion is drawn out. This hardens quickly
and the egg is left at the tip of the thread. The larva? on

Fig. 121. — Chrysopa oculata: newly hatched larva, with under side of
head and claw at side — greatly enlarged. (From Marlatt, Div. Ent., U.
S. Dept. Ag.)

hatching eat up the plant lice in the immediate vicinity.
They are active and run about readily and have prominent
jaws which are sickle-shape, tubular, and adapted for suck-
ing the body fluids of the plant lice. When they have passed
the larval stage they form a small spherical cocoon in which
they pass the pupa stage and from which the adults emerge

ORDER MECOPTERA 169

shortly afterward. They produce a number of generations
each year.

Ant Lions (Myrmelconidoe). — ^The ant Hons are closely
related to the preceding. They look much the same, and
the only difference is the large antennae which stand out
and are thickened at the tip. They have large, equal-sized
wings and long, cylindrical abdomens. The wings are, dis-
tinctly net-veined. These ant lions appear in midsummer
as adults and eggs are deposited presumably in the latter
part of the summer. Whether they pass the winter in the
egg stage or whether the larvse are partially developed is
uncertain. But during the early part of the season and a
large part of the summer the larvae may be found in sandy
places forming little pits in the sand in the bottom of which
they secrete themselves for the capture of ants and other
small animals which may wander into the pits. They travel
backward in changing their location, moving just beneath
the surface and leave a very definite furrow on the surface
of the sand. At one end of the furrow is usually a pit where
the larva is secreted. After acquiring their growth they
build a little spherical cocoon and within this they change
some time later to the chrysalis stage. The adult stage is
reached in, possibly, a two-year cycle.

Order MECOPTERA (Scorpion Flies).

In this order the species are usually four-winged, although
in some cases the wings are reduced or aborted. The wings
when occurring are not folded, have numerous veins, and
often are marked with distinct spots or blotches. The head
is much modified, being elongated so as to form a sort of beak
at the end of which are the small mandibles and the other
mouth parts. The metamorphosis is complete and the larval
stage is somewhat caterpillar-like in general structure.

The order includes the family PanorpidcB and in this
family are a number of common species, but few of them have
any particular economic importance. They have usually
eight pairs of prolegs or abdominal legs so that they may

170 NEUROPTERA AND ALLIES

be distinguished from the lepidopteroiis larvse which have,
as a rule, only five pairs.

The species of Jlitfacus are somewhat common, usually
found in woodland, and have some resemblances to the
crane flies, but are easily distinguished by the presence of
four wings. The genus Bore us is remarkable for appearing
in the winter time and occurring in great numbers on the
surface of snow.

Order TRICHOPTERA (Caddice Flies).

This order is of particular interest scientifically because
it appears to be the primitive group from which the order
Lepidoptera has been derived. The mouth parts are man-
dibulate, the metamorphosis is distinct, the larval forms
caterpillar-like but all the species are aquatic and show
distinct specialization for aquatic existence. In the adults
the body and wings are covered wdth minute flattened or
scale-like appendages which approach the condition found
in the Lepidoptera and except for the mandibulate mouth
parts the group may be considered as distinctly connected
with the Lepidoptera. In some forms the wings are opaque
and the general appearance is extremely like some of the
minute moths.

Perhaps the most notable feature in the group is the
larval habit of forming cases or tubes within which they live.
These cases are made of a variety of materials, in some
species from minute pebbles, minute mollusk shells, and in
many cases with fragments of aquatic plants or various kinds
of debris occurring in the water. The cases are constructed
shortly after the larvse hatch and are enlarged with the
growth of the insect. The head and thoracic legs are
projected from the tube, and the tube moved around by its
adherence to the posterior part of the body. Some species
have a habit of making delicate nets or traps in the water
by means of which they catch aquatic animals for food,
but in most of the species the larvaj travel around freely and
feed upon aquatic vegetation. The tubes or caddices formed

ORDER TRICHOPTERA 171

by these insects liave been found in rocks of the tertiary
period, so that it may be assumed that the aquatic case-
making habit had developed as far back as this period
in geological times. Aside from the fact that these may
furnish food for other aquatic organisms there is little
economic importance to be attached to them. The adults,
while occurring in abundance, do not feed upon any culti-
vated crops, and they rarely appear in such swarms as the
May flies, so that there is no especial annoyance from their
abundance.

CHAPTER VII.
COLEOPTERA. BEETLES.

The Coleoptera, or the order of beetles, is one of the immense
groups of insects, both in species and individuals. It is also
one of the most distinctly marked groups. In some ways
it is more specialized, in others more generalized. The
wing structure is specialized, the horny front wings which
are useless so far as flight is concerned being modified to
serve as covers for the wings and for the abdomen. The
hind wings are the organs for flight. Reduction of the front
wings is to be noticed in a number of cases and in some
species they cover only a small portion of the body.

The Coleoptera and Dij)tera so far as Avings are concerned
are about equally specialized. In the mouth parts the Cole-
optera are very much less specialized than the Diptera — they
retain the primitive structure. The mandibles are some-
times reduced but are functional in the adult stage and
sometimes very strongly developed. They are not modified
into suctorial organs.

The metamorphosis is complete and the stages quite
distinct. There are the four stages common to insects with
complete metamorphosis and in some groups the larva? are
further specialized, so that there are two or three different
larval forms (hypermetamorphosis) . The beetles have been
studied perhaps more than any other group unless it be the
Lepidoptera. They are more easily preserved than most
insects and often of striking form or conspicuous colors.
The beetles probably number at least 100,000 species, and
in this country 10,000 or 12,000 species are recognized.
A considerable number of these are of economic importance.
The group is separable into two quite distinct divisions.
(172)

GROUND BEETLES

173

the Rhyncophora are the more speciaHzed. The head is
drawn out in a snout and the mandibles are much reduced
in size. The larval forms are more specialized, usually fitted
for living within seeds or parts of plants.

In the arrangement of families the tiger beetles are usually
placed first, but it would seem fully as proper to place Cara-
bidcB in this position.

Tiger Beetles (Cicindelidce).— The tiger beetles are found
along roadsides, bare ground, or sandy beach. It is not easy
to get the larval forms. The larvae are carnivorous and
make little burrows in the earth and catch insects that come
along at the surface.

Fig. 122. — Caiosoma scrutator .

Fig. 123. — Lebia grandis,
an important enemy of the
potato beetle. Enlarged.
(Chittenden, Div. Ent., U. S.
Dept. Ag.)

Ground Beetles {Carabidce) .—The ground beetles are less
specialized. They h\e usually at the surface of the ground
and the lar\'8e are provided with three pairs of normal legs
and run about readily and are in fact quite primitive in
appearance and habits. They are, as a rule, carnivorous,
but a few species attack plants.

Some of the more important beneficial species are the
common ground beetle (Calosoma calidum), a black species
with a series of metallic golden spots, abundant over a large
part of the United States, and which feeds commonly on

174 COLEOPTERA— BEETLES

cut worms, caterpillars, etc. The searcher Calosoma scruta-
tor, a brilliant green species with metallic border on elytra
and margin of prothorax which, while a general feeder on
ground-living insects, is also credited with climbing trees
to feed upon canker worms. The Calosoma sycoyhanta, an
old-world species that is especially useful in keeping the
Gipsy moth in check, has been introduced into Massachusetts
in hopes that it may assist in control of this pest.

There are several families of aquatic Coleoptera which live
almost entirely in water, although at times the adults issue
and fly. The carnivorous water beetles ( Dysticidce) have
peculiar circular or oval sucking disks on the front legs, and
are distinctly aquatic, the adults appearing out of water,
and like the ground beetles, they feed quite exclusively upon
other animal life and doubtless occupy a somewhat impor-
tant place in the relations of aquatic forms.

The HydroiMlidcB are more distinctly herbivorous and
may be considered as water scavengers, feeding upon vege-
table debris and serving as important members of the
aquatic association. It is a large family, including a great
many genera and species, but from their habits are naturally
of little economic importance.

The Gyrinida^ or whirligig beetles are quite remarkable
for their movement on the surface of water. They dart
around with the greatest rapidity, making all sorts of irregu-
lar movements but when a group of them are together they
form a bewildering array of darting forms. Although
dozens or even hundreds of them may be in a group they
seldom if ever seem to have a collision among the different
individuals in the cluster. A remarkable feature in their
structure is the separation of the compound eye at the side
of the head so that the upper portion is above \Vater and
the lower portion submerged. They are said to feed mainly
upon flies and stranded insects of various kinds that are
caught on the surface of the water. One of our common
species is tlie Dinniies americana.

Family Platypsyllidse. — The Plafypsyllida' is a small
family including a very remarkable parasite of the beaver.

FAMILY C0CC1NELLID.¥. 175

The female is about 2\ mm. in length, and ovate in form with
very short wing pads so that the abdominal segments are
exposed. Tlu' eyes and wings are both aborted.

Family Silphidae. — The Sil/phidcp, carrion beetles, are
xery distinctly scavengers and where there is an accumu-
lation of decaying organic matter they doubtless serve a
valuable function in disposing of such material that is
detrimental.

Sexton Beetles ( Necrophorns). — ^The sexton beetles are
the largest of the family. They bury small mammals such
as rats or mice and upon these lay their eggs. The larva
then feed upon the decaying flesh.

The species of Silpha are commonly found about dead
fishes or carcasses of dead animals and both the adults and
larvpe feed upon the rotting material.

Rove Beetles {Siaphylinidce). — The Staphylinidoe are also
largely scavengers. The group is a very large one including
many hundreds of species. They are characterized par-
ticularly by the structure of the wdng co^^ers which extend
only to the base of the abdomen. The hind wings are
folded by means of hinges on the wing margin so that they
can be attached luider the short wing-covers. The abdomen
is left exposed and as the joints are flexible it can be moved
about readily and the tip is used in manipulation of the wings
preparatory to flight, or when they are folded after flight.

Several other families related to this division must be
passed over.

Family Coccinellidse. — Lady Bugs. — These are abundant
and very important insects, since practically all the members
of the family are carnivorous and feed upon insects which
for the most part are very destructive. They are especially
serviceable in the control of plant lice and scale insects.
The adults are short, generally hemispherical or oval,
convex above with under side flattened. Usually they are
rather conspicuous: some are red with yellowish or black
spots, while others are black with red or yellowish spots.

The larvae are very voracious insects and feed quite ex-
clusi\ely upon insects, so that they are considered of special

176 COLEOPTERA— BEETLES

service and pains should be taken not to destroy them. They
are short, flattened, rather broad, and usually with rather
prominent spines or hairs as indicated in the accompanying
figures.

Fig. 124. — A lady bug (Hippodamia conve.rgens) which preys on the
Colorado potato beetle. Enlarged. (Chittenden, Div. Ent., U. S. Dept.
Ag.)

Fig. 125. — Spotted lady bug (Megilla maculata): a, larva; b, empty
pupal skin; c, beetle, with enlarged antenna above. All enlarged. (From
Chittenden, Div. Ent., U. S. Dept. Ag.)

A number of species are abundant and of special service
in various parts of the Ignited States. Some of these are
figured, and further description will be vmnecessary.

FAMILY CUCUJID.E

177

Vedalia. — One species of i)articular interest is the Vcdalla.
Tliis was introduced into California for the purpose of con-
trolling the cottony-cushion scale and was so efficient in this
respect that the scale insect has become of little economic
im])ortance.

Family Cucujidae. — Saw-toothed Beetle. — The family Cucu-
jidoe includes, with other pests, the saw-toothed beetle
{Sylvanus surmamensis), probably one of the most frequently
noticed pests of stored cereal foods, especially those in
packages. It is a little, dark red-brown beetle with the

'^ita^^^ff^

Fig. 126. — Adalia bipunctata: a, larva; h, mouth parts of same; c,
claw of same; d, pupa; e, adult; /, antenna of same. All enlarged. (From
Marlatt, Div. Ent., U. S. Dept. Ag.)

edges of the prothorax strongly toothed. It is found in a
great variety of food substances, including breakfast foods,
yeast cakes, nuts, and dried fruits.

All stages of the insect may occur in these substances,
the larva being a slender, somewhat flattened creature, the
pupa being about the shape of the adult. The adult tunnels
through cases or migrates from place to i)lace, depositing its
eggs adjacent to the materials in which the lar\{Te will grow.
There are probably scNcral generations each year, especially
in the food materials that are in warm situations. They
should not be ]3resent in fresh-packed cereals, but owing to
12

178

COLEOPTERA— BEETLES

tlie fact tliat they become very numerous in mills it is quite
probable that eggs may be included in the i)ackage and the
larva^ de\el(>ped later.

Family Lyctidae. — The family Lydidce includes a number
of wood-feeding species, for which the powder-post beetle
{Lydvs planicoUis) will serve as a fair example.

Dermestidae.— The Dermestidoe are forms that live on
decaying animal matter. Good examples may be found by

Fig. 127. — The saw-toothed grain beetle: a, adult; b, pupa; c, larva
or grub. Greatly enlarged. (After Chittenden, Div. Ent., Bull. 4, n. s.,
1896. U. S. Dept. Ag.)

examining dead fish and other decaying organic matter.
Some of the species are museum pests, and troublesome in
bird collections, and a very particular pest of insect collec-
tions. On account of this it is necessary to keep collections
in insect-proof boxes or else fumigate with carbon bisulphide.
Larder Beetles (Dermestes lardarius). — The adults appear
particularly in early summer and the eggs are deposited on
or near materials that furnish food for the larva^. The eggs

FAMILY DERMESTIDJE

179

require probably only a few days for hatching, long enough
when laid on insects, so that it is possible for the insects to
be transferred from one box to another and to introduce
them into new boxes. In case of hams and bacon, these
eggs may be on the hams when they pass from one dealer
to another. The larva; grow most rapidly during the sum-
mer months and if there are any distinct broods it would
be the rapidly developing generations in the summer time.
But the broods are not very sharply marked. There may
be two or three broods, but the development is irregular
enough; so that they are developing at all times of the year.
The larvae do the feeding and devour the tissue, and the

Fig. 128.— a powder-post beetle {Lyctus vlanicollis) : o, larva; 6, adult; c,
pupa; line to right of adult represents natural length. (Chittenden, Div.
Ent., U. S. Dept. Ag.)

pupation takes place early. The larvae may burrow through
paper or wooden cases and then give rise to adults in a
comparati\'ely short time.

Museum Beetle. — A related species — the museum beetle —
is more a musciun pest and less a pest in other ways. It
lives in skins of mounted animals and other dried animal
tissue.

Carpet Beetles.- — Closely related is the carpet beetle, which
is a pest in fur and woollen goods and seldom if ever known
as a pest in museums. It is fond of woollen carpets and
furs. These seem to be its particular food supply. It was
introduced from Europe and has spread over the entire

180

COLEOPTERA— BEETLES

country but is not very abundant for the most part. It
is less abundant where rugs are used than where carpets are
used.

Click Beetles (FJatcrida'). — (Mick beetles are interesting on
account of structure and their habits which are of economic
importance. Tliey make a sudden click and throw them-
selves up into the air. This is produced by a little spur on
the prothorax which fits into a little pit in the mesosternum.
This is characteristic of the entire family and is not found
in any other family. Its purpose is to throw the insect into
the air and allow it to turn over. The larvie are called

V

1

\

yM

-f*

5

y m

1

M

Fig. 129.

-Click beetle tind wire worm (Alelanotua cominutiis):
beetle. (After Bruner.)

larva; b,

wire w^orms. These are very troublesome ])ests. Many of
them are primarily grass-root feeders and will be found as
larvse in grass lands, the larvae li\'ing just below the surface
of the soil, and feeding mainly on the roots of the grass.
When the land is plowed and planted in corn or some other
crop the wire worms attack this other crop, sometimes in
a much more noticeable manner than they do the grass.
The larvae are not capable of migrating very great distances,
and must depend on the ^'egctati()n that is present where
they are hatched. The length of the larval period is shown
by their presence in a field of corn three years after it has

BUPRESTTDJi 181

been plowed from grass. Many of the speeies have never
been traced through in detail, but those that have been traced
show them to be grass-feeding species, and the eggs are
deposited on grass lands. There are some species whose
larvae occur in rotten wood and a few have a phosphorescent
property. These are not of economic importance.

Buprestidse. — The Buprestidcp have larvje that are wood-
boring in liabit and on account of their shape — the very
broad anterior segment of the body — are called the flat-
head borers. Destructive species occur in maple, apple,
hickory, and a considerable number of common trees. The
best-known is the flat-headed apple-tree borer {Chrysobo-
thris femorata), which affects apple and also maple, and
perhaps other trees. The adult is a somewhat flattened and
elongated oval beetle with rather shallow metallic pits on
the wing co\ers. They appear in early smnmer and will be
found running about over the bark of the trees where the
sun strikes them, and the eggs are depositefl on rough
spots of the bark and hatch in a short time. The larvae
burrow just beneath the bark and burrow out a shallow cavity,
limiting themselves to the cambium at least in the earlier
part of their li\'es. The cavity eaten out may be one-half
to three-quarters of an inch wide. The head is small but the
first segment of the body is quite large and flat and is per-
haps rather naturally taken to be the head by ordinary
observers. The remaining segments are slender and nearly
cylindrical. It lies in the cavity in a flat position. The
burrows never go down into the heart of the tree but they
produce dead patches in the growing wood at the surface,
and if they are numerous they may form a girdle and cut
oft' the sap. The larvae make their growth two or three feet
from the ground on apple trees and occur about the lower
branches and a few may girdle the tree. The cycle of the
species is completed in a year. The larvie burrow during
the summer and autumn, are dormant through the cold
weather, and pupate in the spring, the adults appearing in
the summer. The species is usually restricted pretty closely
to one kind of })lant.

182 COLEOPTERA— BEETLES

Lampyridae. — The fire-fly family is quite an exceptional
one, and is very interesting on account of the brilliant phos-
phorescent property. This is most commonly observed
during June and early July and represents the time when
the adults are most abundant. There are a number of
species possessing the phosphorescent organs. The eggs
are deposited and the larvse probably develop during that
same summer, and the pupa stage is reached and adults issue
the following season. They pupate ])erhaps in fall or else
in spring. They are subterranean and are carnivorous and
feed upon the larvae of other species.

Lucanidse {Stag Beetles). — The lucanidse are large forms
with very prominent mandibles which in some species develop
into antler-like structures. The Lucanus dama larva lives
in rotten wood, old stumps, and logs, etc., and only inci-
dentally feeds on living wood. The larvae never start on
living wood. The grubs are large, white, fleshy creatures
with the body curved, almost coiled, and they pupate in the
wood in which they are developed and the adults run over
the ground in timber lands. The adults are quite common
along the beach. They are not adajjted for long flight.

A quite interesting species is the horned Passalus {Passa-
lus cornidus) which Hacs in wood in almost the same manner
as the last species, but the larva is flattened and the adult
quite prominently flattened. The wings are considerably
aborted and the species probably quite limited in its flight.

Scarabaeidse. — The Scarahceidoe are characterized quite
readily by the structure of the antennae. They have a very
specialized form of antennae consisting of a series of small
joints and then a broad terminal structure which is made
up of three or five leaves folded together like the leaves of a
book. These may be separated when the insect is flying.
They are presumed to be the organ of the sense of smell.
There are many sensory pits', and they give evidence of hav-
ing strong olfactory sense, in that they collect at any decay-
ing matter. They are not all scavengers, but they all have
an acute sense of smell. The tumble bugs and a host of
scavenger beetles related to it are included in this family.

SCARABMIDm

183

The Egyptian scaraljs belong here. The tumble bugs
simply enclose their eggs in little masses of refuse matter.
This is to serve as food substance for the larvse, and the}'
shape it in a ball and roll it along until it becomes coated
with earth. The balls are finally buried in the earth. The
eggs hatch here and the larvae develop and get their sub-
sistence from the material in the ball.

Fig. 1.30. — Corpris Carolina, under side. Enlarged. (From photo.)

May Beetles or June Bugs. — Important economic species
are the leaf-eating species. These are species of the genus
Lachnosterna — Lachnosterna fvsca in particular. These are
known as May beetles or June bugs. They are distributed
all through the country. There are perhaps twenty-five or
thirty common species which occur in great abundance
about the same time of the year, but these differ in minute
characters of genitalia. They were formerly all grouped

184

COLEOPTER A—BEETLES

together in one species. They are leaf-eating in the adult
stage. The adults appear rather early in summer, May or
June. They are destructive in the adult stage by cutting
ott" the lea\ es of trees. They do not eat the leaves much
but cut them off at the petiole. Sometimes trees are
completely stripped. They mate in the e\ening when they
fly in great numbers. The eggs are deposited out of doors
and in grass land particularly. The larvae feed on grass
roots, and if this remains available they develo]) there in

Fk;. 131. — Tlie C(iiiinioii Ma\' \)oeth' (Laclinoslirtui fiisca): 1, tlie pupa;
2, the kiiva or white grulj in its ground cell; J and 4. the beetle, side and
dorsal views. (After Riley.)

about three years and when they get fairly near maturity,
about the spring of the third year, they cut off the roots of
the grass pretty severely, sometimes cutting the turf oft'
completely. This causes the same kind of loss as is caused
by cut worms, grasshoppers, etc., or more severe because
of injury below the crown. At this time they are known as
white grubs and are similar in appearance to the larvae of the
stag beetles. If the grass is plowed under and the field is
])lanted to some other cro]) the grubs starve or else attack

SCARABMIDM

185

the other vegetation wliich sometimes suffers severely.
Strawberry beds are quite hkely to suffer. Tliere are no
satisfactory remedies. About tlie only thing that could be
of much use is attention at the time of egg deposition. Ai)pli-
cation of kerosene has been reported in some cases as suc-
cessful on small areas such as lawns or parts of park land.

Rose-chafer (Macrofhicff/Ius subsinnosus, Fab.). — ^The rose-
chafer is a small, yellowish-brown beetle, about one-third
of an inch in length, with very long legs. It occurs in great

f A

'f

Fig. 132. — Rose-chafer {Macrodactylus suhspinosus): a, female beetle;
?», anterior part of male; c, pygidium of male; rf, abdomen of male; f, pupa:
/, larva. All enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.)

numbers at the time of the blossoming of the garden rose,
and will in a couple of weeks entirely strip the bushes of
blossoms, leaves, and fruit. It also attacks the grape,
apple, pear, cherry, peach, and other fruit trees, but is
especially injurious to the rose and grape.

The ravages of the rose-chafer are common in eastern
United States and Canada. The date of the first appearance
of the rose-chafer varies with the season but it is usually
as early as the first of June. They begin mating imme-

186

COLEOPTERA— BEETLES

diately after emerging from the ground. They continue feed-
ing from four to six weeks and are almost constantly paired
during this time. The eggs are deposited singly a few inches
below the surface of the ground, each female laying from

-<4 'v*

lyMi

1

Ira

Fig. 133.— Rosc-cliafer work. (Photo from Ohio Exp. Sta.)

twenty-four to thirty-six eggs. The larva hatches in al)out
two or three weeks and begins feeding on grass and tender
shoots. The larva is mature in the autumn and digs down into
the earth where it builds a small earthen case in which it

CERAMBYCIDM 187

passes the winter, pupating in the early spring and emerging
as adult early in June.

There have as yet been no very successful methods of
control discovered. Heavy spraying with arsenate of lead
when the beetles appear will kill those feeding on the
poisoned leaves, but if very abundant, successive attacks of
newly appearing individuals may make this of little avail.

The Cerambycidae. — The wood-boring beetles show quite
a different habit from the subterranean forms. They are
called the long-horned borers and have very long antennae
with usually eleven joints. In the genus Prionus the number
is greater. The length of the antenna? is produced by elonga-
tion of the joints. In some species the antennse are two or
three times the length of the body. They are typically
wood-boring, and all except one or two genera are borers
in the heart-wood of woody plants. Gradations between
leaf-feeding and wood-boring are to be seen in a few species
that live in the pith of softer plants, and in a few that are
borers in the roots. The extremes are perhaps to be recog-
nized in those forms that burrow into the heart-wood of
the hickory, maple, etc., and that live in such wood after
it has been cut and killed. The larva? are the borers. Some-
times larvse are found in furniture. They seem to require
almost the minimum of moisture and of air.

Hickory Borer (Chion cinctvs). — The hickory borer is
another species which attacks particularly dead or recently
felled trees. Eggs are laid on the dead timber. The borers
will gather in large numbers on cord wood the first two or
three years after cutting. They sometimes make the wood
of comparatively small value for fuel. It is useless for
manufacturing purposes. One remedy is to use the wood
rather promptly after cutting, within a year. Cutting in
the fall is recommended by woodmen, also stripping bark is
said to act as a preventative. They do not work during the
cold weather. The adults occur only in the summer.

Round-headed Borers (Saperda Candida). — The round-
headed borers are among the most common pests of orchards
and their life-cycle includes about three years. The adult.

188

COLEOPTERA— BEETLES

which is brown with two conspicuous white stripes, appears
in early summer, May or June, deposits eggs at the lower

Fig. 134. — Chion cinctiis: a, eggs, natural size; (>, egg, enlarged; c,
larva; d, pupa; e, adult male; /, antennie of female. (After Osborn,
in Garden and Forest.)

l)art of the trunk, near the ground. The larwT on hatching
burrow into the tree and for the first season live near the
bark, then they burrow down and pass the winter in the

Fig. 13.^.— \\'Grk of hickoij
section of stick with burrows.
Garden and Forest.)

borer, ^lH>wiii- I.Migi
One-half natural size.

(After Osljorn, in

lower part of the burrow, perhaps below the surface of the
ground. The next two summers are spent in boring upward

CERAMBYCID.^

189

and inward to the lieart of the tree and then boring toward
the surface, lea^'ing only a thin layer of bark. Before pupat-
ing the larva packs the burrow with chips, then withdraws
a little from the surface to j)upate. The fully grown larvae,
puptc, and adults may all be found in the spring of the same
year. All mature and liecome ready to deposit eggs about
June. The adult has simply to work its way through the
thin packing of chips and a little bark to reach the surface.
It does no real boring in the wood. Few of the species
ha\^e the abilit\' as adults to cut awav the heart-wood.

Fig. 1o6. — Saperda cundidu: a, larva, from side; /), from aoove;
female beetle; d, pupa. All enlarged one-third. (After Cliittenden, Div.
Ent., U. S. Dept. Ag.)

There are two means of control. One is to protect the
trunk of the tree by means of applications of alkali washes,
paint, etc., to prevent the depositing of eggs. Barriers
placed around the trunk are used, such as wire netting, tarred
paper, and building paper, or even several thicknesses of
newspapers. Where such material is used it is better to
remo\e it later in the season (by September first) to give
the bark its normal exposure. Another way is to cut out the
larvse in the autumn of the first season; the burrow close

190

COLEOPTERA— BEETLES

to the bark can be found by means of the chips that are
forced out and project from the burrow or drop to the
ground and form Uttle piles. The grub can be cut out with
a clean sweep of the knife and the wound covered with a
little wax, thick paint, or something of the kind to prevent
entrance of water and formation of decaying spots.

Leaf Beetles (Chrysomelidw). — The leaf beetles represent
rather more primitive habits and have rather more primi-
tive characters than CerambycidcB, the antennae being short
and filiform, but are similar in the character of the tarsi.
The larvae of Chrysomdidw with a few exceptions feed on the
leaves of plants in a very exposed manner and the adults
feed, so far as they feed at all, on the leaves of different kinds

Fig. 137. — Colorado potato beetle {Lepliiiotarsa decemlineala) : a, beetle;
b, larva; c, pupa. Enlarged. (Chittenden, Div. Ent., U. S. Dept. Ag.)

of vegetation. They are sometimes restricted to certain
plants and sometimes have a ^'ariety of hosts.

The Colorado potato beetle (Leptinotarsa decemlmeata)
was at one time a much-dreaded pest but can now be easily
controlled. It occurred originally in the Rocky Mountain
region, feeding on wild plants related to the potato, but with
the introduction of the potato and abundance of food it
multiplied rapidly, migrated eastward and soon spread over
the entire country. It has two generations each year, adults
hibernating in the ground, appearing in early spring and
laying eggs on first-appearing potato vines. The larvae
which hatch soon feed on the leaves, maturing in a short
time, pupating under ground, and a summer generation of

CHRYSOMELIDM

191

beetles appears in midsummer. These lay eggs, and larvje
may be very abundant in late summer, pupate in early fall,
and gi^'e rise to beetles that hibernate. Spraying with
arsenical solutions is effective in their control.

Agriculturally a little group of beetles, the Diahrutica,
are very important. They present an exception to the gen-
eral habit of the family in that they attack roots under the
ground. There are three species of interest. The best-
known species is the striped squash beetle ( Diahrotica

Fig. 13S. — -Striped cucumber beetle {Diahrotica vittaia): a, beetle; h,
larva; c, pupa; d, egg; a, h, c, much enlarged; d, more enlarged. (After
Chittenden, Div. Ent., U. S. Dept. Ag.)

vitfata), a pest to scjuashes and melons, which is an extremely
well-known species. It feeds on stems and leaves close to
the ground and, as larva, in the young squashes, and per-
haps represents the intermediate stage between stem and
root-feeding species.

Diahrotica kmgicomis, the corn-root worm, is distinctly
a root-feeding species. The beetle appears in late summer
and autumn and is a rather bright green little beetle with
no markings. It is found in late summer on the corn stalks,
on^the fall flowers, such as asters, sunflowers, goldenrod,

192

COLEOPrERA— BEETLES

etc., and feeds perhaps on the j>ollen of these flowers. In
some cases it is quite remote from the corn fields. They
deposit eggs in the ground. The eggs remain over winter
and hatch the following spring shortly after the corn begins
to grow, and the larva commences feeding on the corn roots.
While the roots are small they commence at the end and
work along the root; after the roots are larger they work
into the roots. They cause the ears to l^e small and when
numerous can kill out the entire plant. They get their
growth by the middle of July or first of August, pupate,
and spend a few days in the pupal stage, and issue as adults

Fig. 139. — Western corn-root worm (Diabrotica loiigicornis) : o, beetle;
h, larva or root worm; c, enlarged leg of same; d, pupa — all enlarged;
c, more enlarged. (Chittenden, Div. Ent., T'. S. Dept. Ag.)

in autumn. There is a single brood in a year. Rotation of
crops serves as an almost absolute means of pre\ention of
injury from this species. It was most troublesome in the
corn regions of Illinois where corn was planted year after
year on the same ground.

The other species with this habit is also destructive to
corn ( Diahrotica 12- inmctat a) . It is known as the Southern
corn-root worm. It is also troublesome to some other
plants, so that its control is not so easy or certain.

The elm-leaf beetle, an introduced species which has been
a very serious pest in the Atlantic States, has recently

FAMILY BRUCHID.E

193

occurred in Ohio. It has worked westward from some
infected centre in the east, and is apparently spreading over
the country in general.

The cucumber flea l)eetle and grape-\ine flea beetle also
come in this group.

Family Bruchidse.— The family Bruch'uUv in some respects
approaches very near the snout beetles. This includes the
pea and bean weevil and the species are essentially seed-

FiG. 140. — Southern corn-root worm (Diahrotica 12-punctata) : a, beetle;
6, egg; c, larva; d, anal segment of larva; e, work of larva at base of corn
stalk; /, pupa. All much enlarged except e, which is reduced. (After
Riley, except /, after Chittenden, Div. Ent., U. S. Dept. Ag.)

eating forms. In case of the pea wee^•iI the eggs are laid
out of doors on growing pea pods and they burrow into the
pod and get into the growing peas, usually one to each ])ea.
They grow with the growing pea and remain in the pea to
pupate and then later the adults are found in stored peas
in winter and spring. Immense numbers of these larvse
are destroyed by the eaters of green peas but the species
holds its own. It does not become noticeable except in
stored peas. The Iar\fie at the time of green peas are small
13

194

COLEOPTERA— BEETLES

and soft, probably of a good flavor like the pea, and do not
attract any attention at all. The way of preventing its
occurrence is to pick out the infested peas and treat them
before planting. Soaking in cold water for several hours

Fig. 141. — Elm-leaf beetle (Galerucella luteola): a, e, eggs; b, g, larvse;
c, k, adults; /, sculpture of egg; h, side view of segment of larva; i, dorsal
view of same; j, pupa; I, portion of elytron of adult: a, b, c, natural size;
0, j, k, somewhat enlarged; e, h, i, I, much enlarged; /, highly magnified,
(From Riley, Div. Ent., U. S. Dept. Ag.)

kills the adults and prevents egg deposition. Warm water
may be used and will hasten the death of the larva but it
must not be so hot as to kill the germ. Buggy peas will
germinate usually just as readily as the sound ones but
have less material to grow on. Peas that are kept in bins

RHYNCOPHORA

195

or sacks where the ackilt cannot get out can do no harm to
the new fields. Fumigation of the seed is one method of
destroying the beetles. In some places it is required by law.
The Ehyncoyhora or snout beetles are distinguished by
the elongate head drawn out into a narrow and sometimes

K--^/>f ! /

m '11/
J \'f

Fig. 142. — The clover-leaf weevil (Phytonomus punctatus): a, egg;
h, b, b, b, larviE feeding; c, recently hatched larva; d, head of same from
beneath; e, jaw of same; /.cocoon; (7, meshes of cocoon ; /t, pupa; t, beetle;
j, same in outline; k, same dorsal view; I, tarsus of beetle; ?w, antenna of
same; b, f, i, natural size; others more or less enlarged. (From Riley,
Div. Ent., U. S. Dept. Ag.)

very long "snout" at the end of which the minute mouth
parts are attached. The larvae are commonly found as
grubs in seeds, nuts, etc., but the clover-leaf weevil and the
alfalfa weevil feed upon the leaves and stems of clover and
alfalfa.

196

COLEOPTERA —BEETLES

Plum Curculio {Conotrachehis nenuphar, Herbst.)- — This
pest is still one of the main difficulties in the way of raising
good crops of plums, but it may be considered at least pos-
sible, by proper care, to secure good crops of perfect fruit.
The beetles hibernate and appear on the trees shortly after
bloom, feeding to some extent on the leaves and young
fruit, and then laying their eggs in the young plums, the
punctures indicating point of deposition being marked with
a crescent-shaped cut. The larvje burrow through the pulp

Fig. 143. — The larger chestnut weevil (Balaninns jyroboscidcus) : a,
female beetle; b, same in outline from side; c, head, rostrum, and antennae
of male. Three times natural size. (Chittenden, Div. Ent., U. S. Dept.
Ag.)

of the plum, not entering the stone. The infested fruit
ripens prematurely and falls from the tree, and the larvae
for the most part lea\e the plums and pupate under ground.
The adult beetles appear in late summer or early autumn
and live over till the following spring.

The beetles drop readily when disturbed, and the well-
known plan of jarring trees daily during the time of egg
deposition in the morning and gathering the beetles on can-
vas spread under the trees is a valuable means of preventing

RHYNCOPHORA

197

their injuries. Spraying with an arsenical sokition has
been found to be useful, and if the plum trees are thoroughly
sprayed once soon after the bloom has fallen and again ten

Fig. 144. — Larger chestnut weevil (Balaninus proboscideus): a, larva;
h, c, female pupa; d, eggs. All enlarged. (Chittenden, Div. Ent., U. S.
Dept. Ag.)

Fig. 145 Fig. 146

Fig. 14,5. — Balaninus proboscideus: head of larva, much enlarged. (Chit-
tenden, Div. Eut., U. S. Dept. Ag.)

Fig. 146. — Pecan weevil (Balaninus caryce): o, female, dorsal view
b, same, lateral view, in outline; c, head with rostrum and antenna of^male.
About two and one-half times size. (Chittenden, Div. Hint., U. S. Dept.
Ag.)

days later, it will greatly help in securing perfect fruit.
Some experiments have shown extremely valuable results
in this direction.

198

COLEOPTERA— BEETLES

The nut weevils have enormously elongated snouts
They infest chestnuts, pecans, acorns, hazel-nuts, etc.

Fig. 147. — Hazel-nut weevil (Balaninus obtusus) : a, adult female, dorsal
view; 6, head from side; c, head of male from side. Enlarged. (Chittenden,
Div. Eiit., U. S. Dept. Ag.)

Fig. 148. — Boll weevil {Anthonomus grandis): rt, adult beetle; h, pupa;
c, larva. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.)

Cotton-boll Weevil.^ — In the Southern States we have a
most striking case of introduction and dispersal in the
cotton-boll weevil, which came into southern Texas from
Mexico about the year 1890 and has been making steady

200

COLEOrr ERA— BEETLES

progress throughout the cotton-growing States. It is a small
beetle somewhat like the clover weevil but restricted to the
cotton plant for its food and for the early stages is restricted
to the bolls of cotton for its particular food. This means
that it can develop only in places where cotton grows and
at such time as the cotton bolls are in process of develop-
ment. This species has practically revolutionized the agri-
cultural conditions of the Southern States in which it has
spread, and it is unnecessary to say that it must have had

Fig. 150. — White-pine weevil {Pissodes strohi): a, adult, smaller figure
natural size; h, larva, line at left natural length; c, pupa, small figure of
adult showing natural size. (Hopkins, Div. Ent., U. S. Dept. Ag.)

a very pronounced influence upon the other kinds of insects
or animals that occur in that region.

The ma]:» illustrates its progress from year to year and it
is a matter of considerable interest antl significance that
the northern border of its distribution has remained inside
the jjossible area of cotton growth. It may also be noticed
that this line agrees remarkably for the northern distribu-
tion of the cattle tick and other insects which are of tropical
derivation.

RHYNCOPHORA

201

Fig. 151

Fig. 152

Fig. 153

Fig. 154

Fig. 151. — Hylastinus obscurus: adult in,sect — natural i-ize at right.
(Webster, Div. Ent., U. S. Dept. Ag.)

Fig 152. — Hylastinus obscurus: larva or grub — much enlarged. (After
Webster, Div. Ent., U. S. Dept. Ag.)

Fig. 15.3. — Hylastinus obscurus: pupa — much enlarged. (After Webster.)

Fig. 154. — Clover root, showing work of Hylastinus obscurus. Slightly
enlarged. (After Webster, Div. Ent., U. S. Dept. -Ag.)

202

COLEOPTERA— BEETLES

Fig. 155. — Scolytus rugulosus' a, beetle; b, same, in profile; c, pupa;
d, larva. All magnified about ten times. (Bur. Ent., U. S. Dept. Ag.)

s-

Fig. 156.— Scolytus rugulosus. Section of injured tree. (Photo from
Ohio Exp. Sta.)

RHYNCOPHORA

203

The insect hibernates as an adult and may be carried by
shipments of cotton seed or other objects. The eggs are
laid on cotton bolls in early summer and the larvas feed
within the bolls, ruining the fibers that would form the
crop.

Fig. 157.— Dcndroctor,

v(tU:iis: adult. (A,
U. S. Dept. Ag.)

D. Hopkins. Bur. Ent.

Diversified farming, the clearing up and burning of old
cotton plants in the fall and early planting are some of the
measures used in efforts to control the species.

The white-pine weevil is a destructive species in the pine
forests of the Northern States and Canada and occurs south-
ward along the Allegheny range to North Carolina.

Scolytidse or Engraver Beetles and Bark Beetles. ^These
are interesting because of their forming characteristic mark-

204

COLEOPTERA— BEETLES

ings between the bark and the wood. They are a great
economic pest in forests. The pine forests of Virginia,
Georgia, etc., and tlie Black Hills have been greatly injured.

Fig. 158. — Dendroctonus valen^: work in bark at base of stump: a. en-
trance and pitch tube; b, egg gallery; c, boring dust and resin; d, pupal
cell; e, pupa; /, larvae at work feeding on inner living bark; £/, exit burrows;
h, resulting old scar or basal wound, often referred to as basal fire wound;
i, inner bark with outer corky bark removed. (A. D. Hopkins, Bur. Ent..
U. S. Dept. Ag.)

RHYN COP MORA 205

One of the destructive species {Ilylastinus ohscurns) is a
borer in the roots of clover and occasions much injury to this
crop.

Fruit-tree Bark Beetle (ScoIi/fN.s riKjulosus). — The fruit-tree
l)ark beetle is a common pest of orchard trees and the cause
of much injury. Its work becomes apparent in numerous
small round holes in the bark. Shot-hole borer is one name
for the species, based on this feature.

The species of Dendroctonus are mainly destructive to
forest trees, and are responsible for extensive inroads on
our forest resources.

CHATTKR VIII.

LEPIDOPTEIiA.

The Lejndojjtera form one of the largest orders of insects
including a great number of subdivisions and including
some of the most brilliant forms and some of the extremes in
size — moths, butterflies, etc. They are separated from all
other insects by the mouth structure, it being adapted for
lapping up nectar of flowers and this structure being devel-
oped largely from the maxillae, the parts being elongated

MESOTHORflK
M£TATHOR/iK \

P/KlTMOfAX

Fig. 159. — Tomato worm (larva of Phletjethontius 5-maculata), showing
structure of lepidopterous larvae. (Drawn by J. I. Hambleton /)

and extended for some lengtli when in use and when not
in use folded up like a watch spring. Some forms have
remnants of rudimentary mandibles but in most cases these
cannot be found. When they occur the mouth parts seem to
be in their general structure related to the Trichoptera.
The larvse are all mandibulate. Another distinctive character
is the complete covering of body and wings with minute
scales.

The Lepidoj)iera show quite extreme condition in meta-
morphosis. The larvae are known as caterpillars. They
(206)

BAG-WORM MOTHS

207

usually have a series of prolegs or false legs developed on
the abdominal segments. The more common number is
ten, four pairs located on the central abdominal segments
and one terminal pair. These are not homologous with the
segmentally jointed appendages of insects generally. They
stand out prominently and are fitted commonly with rows
of small hooks or teeth at the margin. The larvae are elon-
gate and generally cylindrical and are followed by a pupa
stage strikingly different from the larval stage and fre-

FiG. ICO. — Bag worm (Thyridopieryx ephemercrformis): n, full-grown
larva; h, head of same; c, male pupa; d, female pupa; e, adult female;
/, adult male. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.)

quently enclosed in a cocoon. This is a quiescent stage.
The adult on issuing splits the pupal case along the dorsal
portion and crowds its way out.

Bag-worm Moths. — Among the lower forms are the bag-
worm moths. These are forms in which the larvae construct
a case or bag of bits of leaves or twigs with which to protect
themselves. Almost parallel with the habit of the caddice
flies. One of the most common is the evergreen bag worm
{Thyridopieryx eyhcviercBJormis) . Its favorite food plants
are conifera, red cedar, and arbor vitse. It occurs com-

208

LEPIDOPTERA

monly over a large portion of eastern United States. The
bags which are formed by this insect are found abundantly
in autumn and winter and early spring attached to the
trees upon which they have developed. They may crawl
some little distance from the trees and attach themselves to
some other object. Each bag is made up of numerous bits
of leaf and twig, making a regular structure. These bags
in late summer and autumn furnish protection for develop-

FiG. 161. — Bag worm (a, b, c) at successive stages of growth: c, male
bag; d, female bag. Natural size. (From Howard, Div. Ent.. U. S. Dept.
Ag.>

ment of the adult. The females remain within the bag.
They are wingless and grub-like with very large bodies.
The males issue from the chrysalis and fly about with well-
developed wings. After fertilization the females deposit
eggs within the bag, filling the cavity of the bag with a mass
of eggs. This forms the protective covering for the egg
mass during the winter. The eggs hatch in the following
season and the larvse begin feeding upon the foliage of the
tree and begin the construction of a case or bag almost as

BAG-WORM MOTHS

209

Fk;. 162. — Has worm iThiiridopieryx ephemerceformis) cases from
cedar tree.
14

210 LEPIDOPTERA

soon as they begin to feed. The bag is made of silk mixed
with the bits of leaf, etc., and attached to the twig by silken
threads. The metamorphosis to the pupal stage occurs
within the case. There is a marked difference in the size,
etc., of the males and females in the case. They are a
source of injury to evergreen trees, stripping the foliage.
They are a little difficult to contend with. Applications
of poisonous arsenical solutions to the foliage where they
are feeding will kill them. The cocoons may be gathered
and destroyed. The migration from tree to tree is limited
by the migration of the larvse, as the females remain in the
bag and do not travel about. The migrations of the cater-
pillars are limited to rather short distances. This is the best-
known species of the family.

Family Cossidae. — The family Cossidce is another group
presenting adaptations to special food and includes the
carpenter moths — characterized by the wood-boring habit
of the larvse. This is a decided departure from the leaf-feed-
ing habit. The leaf-feeding habit is the most primitive
condition. They burrow into the heart-wood of various
trees.

Locust-tree Borer (Prioiwxystvs rohmioe). — The locust-tree
borer is the most conspicuous. It occurs in other trees
besides the locust. The moths are strong-bodied and
resemble the hawk moths in the shape of the body and in the
narrow form of the wings. The adidts appear in June and
July and deposit their eggs upon various trees and the larvse
on hatching begin burrowing into the tree, living at first
in the cambium and then burrowing deeper into the woody
tissue. The larvae are supposed to require three years for
their growth. The larva is whitish and almost naked with
only a few^ scanty, minute hairs and looks more like the
grub of a beetle than like a caterpillar of a moth. It forms
a rather large tunnel, the burrow when the larva gets full
size being about one-half inch. These burrows frequently
permit the entrance of moisture and so start decay and in
m^any cases cause some distortion; they cause trees to break
easily. Before changing to the pupal stage they bore out to

FAMILY^ PYRALID.E 211

the bark, leaving only a thin layer that has to be pushed off
by the pupa before issuing as a moth.

In another family, Pyralidos, there is one species, the
clover-hay worm (Pyralis costalis), which is very destructive.
They injure the stored crop of clover. The moths of this
species appear in summer, perhaps most abundantly about
midsummer. Eggs are deposited largely in the newly stored
hay and the larvae feed upon this hay. Perhaps the majority
continue their larval life through the winter — the hay
becomes matted and filled with the silken webs they spin
and with the black gunpowder-like excrement they discharge.

■■■/

^

c

: J

/

Fig. 163. — Indian-meal moth (Plodia inter pwictella): a, adult; b, pupa;
c and/, larva; d, head; e, first abdominal segment of larva. All enlarged.
(After Chittenden, Div. Ent., Bui. 4, n.s., 1896, U. S. Dept. Ag.)

The hay, while not all consumed, thus becomes unfit for stock
food. They get their gro^^i;h in the hay and change to
chrysalids and the adults issue and fly about in hay mows
and about hay stacks.

Closely related is a si)ecies known as Pyralis farmalis,
which feeds upon stored grain and also upon clover hay.
The life-cycle is about the same as of the other species.

Indian-meal Moth (Plodia interjmnctella) . — This is another
common pest of food substances. It occurs in somewhat
the same materials as the saw-toothed beetle. It is quite
different, however, the adult being a small moth somewhat
similar to the clothes moth in appearance, although larger.

212

LEI'lDOl'TERA

The eggs are laid in the various food substances, breakfast
food, seeds, dried fruits, etc., and the larva which is a small,
slender caterpillar feeds in this material and usually spins a
web as it works so that the food is made quite undesirable.
There are usually two broods each year in the latitude of
Ohio, but with warmth, the number of generations may be
increased to four or five. As with the preceding species, it
is possible to sift out the insects from the flour or meal but
if infested to any extent their presence is undesirable and
infested packages are best returned to the grocer to exliange
for fresh material. The prevention of their entrance into
the packages of breakfast foods, etc., should be attended
to at the mills or ])acking houses.

Fig. 164.— Mediterranean flour moth {,Epheslia kuehniella): a, moth;
b, the same from side, resting; c, larva; d, pupa; e, abdominal segments
of larva; a and d, enlarged; c, more enlarged. (After Chittenden, Div.
Ent., Circ. 112, U. S. Dept. Ag.)

The direct treatment of these insects in stored products
where fumigation is possible is in store rooms, but cannot be
done as advantageously as in the mills or warehouses or
where the cereals are ])repared.

The Mediterranean Flour Moth {Ephestia knehuieUa).—
This is a destriictixc insec-t, occurring in stored wheat and
other grains, and ])articularly in mills and warehouses, and
has now been distril)uted oNcr all parts of the world where
grains and their products are stored. It is one of the most
serious pests in the large flour mills of the northern United
States, in some cases clogging and stopping the machinery

BEE MOTH 213

and causing- a considerable loss in the flour, meal, or other
products. Its life-cycle is fairly contiiuious where buildings
are warm enough to permit its growth.

The principal methods of control are by means of heat
and fumigation. Where a heating system is present, and it
is ])ossible to raise the temperature of the building to 125°,
this is a most effective plan and requires but a short suspen-
sion of the operations of the mill. Where this is not avail-
able the use of hydrocyanic gas or bisulphifle fumigation is
necessary, although frequent cleaning of the building and
the careful disposition of insects which are found in the
accumulated dust in different parts of the building will serve
to keej) them in check.

Bee Moth (daUeria mcllonclla). — The bee moth gets its
name from the fact that it li^'es in the hiNCS of honey bees.
It is confined closely to this habit and all stages will be
found in and around the hives. The adults are found
during the summer months particularly and are com-
monly hidden under and around the hives, and if disturbed
tend to slip away, crawling into corners or making a
short flight to some safe place, almost as slippery as cock-
roaches. They gain entrance to the hives by slipping in at
the entrance, especially if the entrance is not well guarded,
they deposit eggs upon the comb doubtless in some corner
where the bees are not numerous. The larva^ feed upon the
wax and make long burrows around through the combs,
x^ccording to Comstock, the larva feeds only at night and
hides in its burrow during the day. They pupate generally
within the hive and upon the tops of the frames or in
the corners, and in some cases probably creep outside and
get underneath the hi\'e. They spin quite a tough silken
cocoon within which they pupate. This stage gives rise
later to the moth. There are at least two generations
during the season. The first measure in the way of pre-
vention is to keep the colonies in good condition and a part
of the treatment may consist in looking over colonies and
catching and killing any moths, larvae, or pupcie that may be
obser\ed.

214 LEPIDOPTERA

Close-wings (Crambidcp). — The close-wings are named
from the jiosition of the wings, which are folded down very
closely at the sides of the body and in many cases they
fit so close to the stem on which they rest that the moth
is completely hidden. Many of them are light yellowish
and straw-colored which blends quite well with the color
of the straw or grass on which they rest. The genus
Cr ambus includes fifty or sixty species, and most of them are
grass-feed in*g species that are to be considered as distinct
pests in pastures and meadows, though they only now and
then multiply in such numbers as to attract universal atten-
tion. These different species present dift'erent life histories
and these must be known in detail in order to treat them
intelligently. The most abundant species in the Mississippi
valley has the following life-cycle. The sod worm occurs in
the adult stage about the latter part of May or the first
of Jime and sometimes in very great abundance. They are
attracted by light. They deposit eggs at the times of flights
and normally deposit these over grass lands, and the eggs
are evidently scattered very generally and are extruded
singly, evidently with some force. They drop into the grass
and on the surface of the ground, and the larwne when hatched
feed at or near the surface or burro^^- a little below the
surface of the ground and form a silk-lined tube in which
they live and are protected mostly during the daytime,
coming to the surface at night to feed upon the fresh leaves.
In this way they cut grass off very near the surface of the
ground and it falls down and dries up, and is lost for hay and
pasturage. The plants are not killed outright. The effect
is similar to that of close pasturing of cows or sheep. If
the insects eat down into the ground the grass may be
killed. They attain their growth in the course of about four
or five weeks and pupate in August and the second genera-
tion of moths appears diu-ing the middle or latter part of
August. These may occur in large numbers if the season
is favorable. These deposit eggs and the larva? from these
begin feeding in autumn and become partially grown but
do not mature, remaining in the lar^■al stage over winter.

FAMILY TORTRICIDM 215

In the following spring they finish their growth, pupating
and issuing as moths in the latter part of May or early part
of June. If the grass land is plowed and another crop put
on it, especially corn, the crop may suffer very severely.
The remedy is to plow the ground early enough in autumn
to prevent egg deposition. If plowed in the spring, it should
be plowed early. They are attracted very generally to light
and trap-lights in fields ought to be very useful. In Iowa,
where ground squirrels (13-striped squirrels) are' common, it
was noticed that the pupae of these sod worms are eaten by
the squirrels. They are also parasitized, and this would
perhaps help to keep them reduced in numbers.

A species with a remarkably different food habit li\es on
the maple scale (scale insects) Coccid-eating.

Family Tortricidse. — This family includes the leaf-rollers
and bud moths. These are characterized by a broatl form of
the wing and are distinctly opposed to the slender, narrow
wings of the Crambus. The costa is very strongly curved.
The mouth parts are not Very conspicuous; head small. The
larvae are mainly leaf-rollers and inhabitants of the buds
of diflFerent kinds of plants. These forms have several
injurious species. Cacaesia roseana is quite common and
troublesome to florists and rose growers. The insects
appear very early in the season. The larvse begin to work
soon after the leaves have begun to unfold. The leaves will
be tied together and the larvae work within this protection
and eat away the tissues of the leaf. In some cases they
burrow into the opening buds and destroy the blossoms.
They attain their growth rather rapidly and form a chrys-
alis often in the leaves they have tied together and from
this the moth issues.

Codling Moth. — The worst pest in the group is the codling
moth (Carpocapsa pomoneUa). This causes enormous
losses to the orchard industry; millions of dollars being
lost each year. Its life history is well known and can be
found in almost any work on orchard insects, but stated
briefly, consists in a spring brood of insects appearing and
laying eggs shortly after apple bloom, a first brood of larvae

216

LEPIDOPTERA

is found in early summer, i)U])ation in early July, second
brood mates about Au<>ust first, and second brood larvje

Fifi. 165. — Codling moth {Cdrpacn psn luniinnrllii): larvie in cocoons upon
bark of apple tree. (Plioio 1)\- Ohio Exp. Sta.)

Fio. 106. — Siiraying for Codling moth (Carpocapsa pomonella).
(Photo by Ohio Exp. Sta.)

FAMILY roTirmciDM

217

in fall and early winter. The essential basis for treatment
lies in the time and place of e.i>j2; deposition. The egg is
deposited in the calyx of the fruit and the larva burrows
into the fruit.

The whole secret of destroying the species is to have the
poison applied placed so that it will get into this particular
])art of the api)le and be there when the lar\a takes its first
meal. Proper ap])lication of arsenical solution will prevent
95 to 98 per cent, of the injury. Application should be
made ver\' soon after the bloom falls while the fruit is still

Fig. 167. — Codling moth (Carpocapsa pomonella) : young apples in
condition for spraying. (Photo by Ohio Exp. Sta.)

open at the calyx end. There are two broods in a season,
The larvfe seen in the apples in the winter are the ones from
the second brood. They escape from the apples when
stored and secrete themselves about the bins and change to
pupse, and the moths are ready to issue early in the spring.
The insects may be captured as pup?e at the end of the first
brood so as to prevent the issuing of the midsummer moths.
This may be done by means of bands around the trees
under which the larvae will crawl to pupate. These bands
may be examined every few days and the i)U])a' crushed.

218

LEPIDOPTERA

The process is somewhat slower and less effective than spray
ing and is now seldom used.

Fig. 168. — Codling moth (Carpocapsa pomonella) : apples too late for
spraying. (Photo by Ohio Exp. Sta.)

A closely related insect, Carpocapsa saltifans, is the basis
for the popular phenomenon known as jumping beans,

FAMILY TORT RI CI DM

219

occurring in beans and some other seeds and causing these
seeds to jump about in a very pecuhar manner. This is
caused simply by the jerking movements of the body of the
caterpillar within the seed.

Clover-seed Caterpillar {GrajjJwlitha interstinctana, Clem.).
— The clover-seed caterpillar is often a serious pest to the
clover seed. Its work, however, is not confined to the seed,
but extends to the leaves, stems, or crown, so that on the
whole its capacity for mischief is very great.

Fig. 1G9. — Codling moth {Carpocapsa pomonclla) : egg.

The moths are very small and may be generally described
as dark brown or nearly black in color. The wing expanse
is from 0.31 to 0.36 of an inch. The majority are marked
by two small parallel, excurved, short, silvery lines at the
middle of the hinder border of each forewing so that when
the wings are closed the lines form a double crescent over
the back. (See Fig. 107, c and d). Some, however, are found
to have all traces of the crescents obliterated. Eight white
silky lines are disposed along the front border of each of the
forewings, which in common with the hindwings are deli-
cately fringed. The wings beneath are shining and silky and
have a greenish tinge in certain lights.

220 LEPIDOPTERA

The larva (Fig. 170, a) is a small greenish-white caterpillar
with a dark l)r()wii head, and is about 0.25 to O.)^ of an inch
long when full grown. Many of them become tinged with
red toward the hinder extremity as they approach the time
of pupating.

The delicate white silken cocoons are spun in the head
among the dried florets, grass, and bits of eroded but un-
devoured flowers, so covering them with brown as to make
them difficult of detection. The pupte work their way
entirely out of their cocoons and drop to the ground before
bursting their pupal cases, which may be found in abundance
on the ground from which a brood has just issued.

V

Fig. 170. — Grapholilha mterstinctana: o, larva; b, pupa; c, adult;
all enlarged; d, adult — natural size. (After Osborn.)

The remedies for the species are summed up as follows:

1. Rotation of crops, not keeping clover on the same
ground over three years, and only two if the field becomes
badly infested.

2. That the seed for a new crop be planted on land as
remote as possible from old clover fields.

o. That infested fields from wdiich seed is desired the
following year be pastured in the fall to take up all late
growths and leave the field free from Acgetation, and that

FAMILY TINEID.E

221

no manure be applied at the time to lurnisli |)laees for the
larvfe to hibernate.

4. That elover infested during the spring be cut as early
as practicable, while the larvae are in the heads, handled as
carefully as possible to prevent shaking larvae from the
heads and stored in stacks or barns, the larvte being found
to perish under such treatment.

5. When ready to change from cl()\'er to ;
plow under some time in October, Xo\ember,
spring burying the larvae as deeply as possible
harrow to pack the surface.

Several parasites have been reared which ^^i
reducing numbers under ordinary conditions.

lothcr crop
or in early
and roll or

assist in

Vui. ni. — Tinea prUnimUn
(From KilcN, 1

;ulult; liirva; larva in case — enlarged.
V. Knt., V. S. Dept. Ag.)

Family Tineidse. — The family Tincid(r includes very
minute moths which have slender wings and usually with
the wings very broadly fringed, and is a specialization or
modification from the typical broader wings. The>^ are
\ery delicate, mostly very minute and the more abundant
outdoor forms are leaf-miners, the lar\'ce li\ing between the
epidermal layers of the leaf and feeding upon the pulp of
the leaf. Some form galls. The tough part of the leaf is
protective at least to a degree. Some also construct cigar-
shaped cases and are known as case-bearers. The best-

222 LEPIDOPTERA

known species are the clothes moths, and they have quite a
speciahzed food habit, being hmited to dry woolen fabrics
or furs. There are three common species, one the case-
bearing clothes moth, one a naked species, and one the
carpet moth which constructs a sort of burrow within the
goods. The life histories are similar, adults appearing in
spring or summer and the larvae feeding in the carpets
clothing or furs, especially during the summer months.
Naphthaline or "moth balls" are a good repellent, cold
storage and storage in moth-tight paper cases are helpful.

Fig. 172. — Tineola biscUklla: moth, larva, cocoon, and empty pupa
skin — enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.)

Sesiidse. — These have a rather unusual condition for the
Lepidoptera. In many the scales are wanting and the wings
look glassy — like wasps' wings. Scales will usually "be found
on the veins of wings and on the body and legs, those on
the legs being quite large. They fly in daylight rather
than at night and there are a number of distinctly economic
species. The larvae are borers and live in the wood of trees
and sometimes of annuals. The squash-vine borer is often
very destructive to squashes, melons, and pumpkins.

One of the most common and destructive is the peach-tree
borer (Sanninoidea exitiosa). This causes serious damage to
peach orchards in the Eastern Central States and southward.
The adults vary a great deal in the two sexes. The females
are larger and a darker steel-blue with a broad orange-yellow

SESIIDM

223

band about the middle of the abdomen. The males are
banded dark and yellow with wings more glassy and body
more slender and considerably smaller. They appear in the

Fig. 173. — Squash-vine borer {Melitlia salyriniformis): a, male moth;
h, female, with wings folded at rest; c, eggs shown on bit of squash stem;
d, full-grown larva, in situ in vine; e, pupa; /, pupal cell. AH one-third
larger than natural size. (From Chittenden, Div. Ent., U. S. Dept. Ag.)

Fig. 174. — Sanninoidea exitiosa: a, adult female; h, adult male; c,
full-grown larva; d, female pupa; e, male pupa; /, pupa skin partially
extruded from cocoon. All natural size. (After Marlatt, Div. Ent., U. S.
Dept. Ag.)

adult stage in midsummer, largely in late July or August,
and deposit eggs near the ground around the trunks of
peach trees and also plum, cherry, and other stone fruits.

224 LEPIDOFTERA

The eggs are deposited in crevices or broken places on the
bark. The great majority are within six or seven inches
of the ground. The larva; soon hatch and bore into the bark
and into the soft sap wood. They hve close to the bark for
a good share of the time. In some cases they are almost
exposed. They do not seem to have developed the habit
of boring so deeply as some others. During the autumn
they continue this boring, growing somewhat, and hibernat-
ing in the larval stage. They go as deep as possible in the
winter. In the spring they continue feeding and extend
the burrows and complete their lar\-al growth in late spring,
mostl\' during May. They pupate within the burrows and
are usually so close to the surface that the pupaj have no
particular (lifficult>' in getting out of the burrows when ready
to change to adults. The length of the pupal life is not
very great. The adults commence appearing in midsummer.
There is one generation for each year. Treatment for the
species has never been very satisfactory. There is no method
known at once cheap and effective that can be easily applied.
The most effective plan is that of cutting out the larvse
from the burrows during the early autumn. A recent plan
of mounding the trees and using a barrier applied close to
the trunk with an adhesiNe that is pliable and non-injurious
to bark, the collar flaring over the mound, is claimed to be
effective.

In the same family are the currant-, maple-, and syringa-
l)orers. The food plant is rather restricted usually.

Handmaid Moths. — Genus Dafana, and species Datana
>iiiiil\ira, ha\'e a quite peculiar habit as larva?. The moths
are rather neutral-tinted forms and the larvae are quite
c()nsj)icuous with a gregarious habit. They occur commonly
on apple trees and other orchard trees, and where there is a
nest of them the trees are badly stripped. They cluster in
large masses and work in a company. At the periods of
moulting they travel down the trunk to within a few feet
of the ground and all moult at once and leave a large mass of
moulted skins which adhere to the bark. After this moulting
they travel back uj) the tree to the leafy i)ortions and ha^■e

FA MIL Y GEO MET in DAi

225

another period of feediiiii". There are probably four or fixe
different moults. At the last moult they are two and a
half or three inches in length and about as thick as a pencil.
They pupate in protected places and remain over winter
in this stage, and the moths issue in the early summer and
deposit eggs. They are very easily controlled. When
clustered during the moulting periods they may be easily
gathered and killed.

Family Geometridse. — The family Geometridw includes
the loojxTs. The larva^ have a peculiar arrangement of legs,
the abdominal legs being lost, except the last pair, and the
movements being made with the thoracic legs.

Fig. 175. — PalcacrUa vernata: a, male moth, b, foiii lU' moth; both
natural size; c, joints of female antenna, d, jumt uf ft-nutle abdomen; e,
ovipositor — enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.)

Canker Worm. — The canker worm is one of the most
important of these species economically. These are typical
loopers and show some distinct specialization. There are
two species closely related, and the>' are known as the fall
and the spring canker worms. The spring form appears as
an adult in early spring generally before the foliage is
expanded on the trees, and the males and females are very
different in their characters. The females are wingless and
the males have broad, thin wings. The females can gain
access to the trees only by crawling up the trunks, and the
possibilities of distribution are limited by the distance which
the females can crawl. They usually crawl up the trunks
of the first tree they reach. The eggs are deposited on the
twigs and hatch al)out the time the leaves are fairly opened.
The larva' are very destructive. In three or four weeks they
15

226 LEPIDOPTERA

become fully developed, and drop to the ground by means
of silken threads. They enter the ground for pupation and
remain in the ground in the pupal stage through summer and
fall and winter.

The fall canker worm is almost the same so far as the life-
cycle is concerned, except that the adults issue in fall. In
this species the eggs remain over winter and hatch early in
spring. Development is quite rapid and pupating is practi-
cally the same as for the other species. The wingless con-
dition, and the fact that they must crawl up the trees, gives
one method of treatment. Anything that w^ill prevent
their going up the tree will protect the trees. Bands of tar

Fig. 176. — Paleacrita rmiata: a, larva — natural size; b, eggs — natural
size and enlarged; c, side view of segment of larva; d, dorsal view of same
—both enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.)

or oil on cotton will prevent their getting up the trunk of the
trees. Small trees may be sprayed with arsenical solution
as soon as they begin work in the spring.

Noctuidse {mvlet moths) include an immense number
of common moths and a number of them very important
species. The common name for the larval forms is cut worm.
They differ from Geometers in adult characters and the wings
are not so broad but fall close together on the back, sloping
down the sides of the body. The hindwings are quite large
but are not marked. The larvae are mostly without distinct
coverings of hair, usually smooth and some of them subter-
ranean in habit.

One common and destructive species is the boll Avorm of
the South, known in the North as the corn worm or tomato

NOCTUIDyE

227

worm. The larva; burrow into corn or tomatoes and do a
great deal of damage.

Another important species is the cotton worm {Alabama
argillacea) wliich causes losses of millions of dollars in the
cotton crop of the Southern States. Occasionally extensive
flights of the moth bring swarms into the Northern States,
and sometimes these adults attack fruits such as peaches,
but it is not believed that the larvse grow on any Northern
plant.

y Ohio

Exp. Sta.)

Army Worm (Leucania unipimcta) . — The army worm is a
widely distributed species in this country, only once in
twenty or thirty years multiplying in such enormous num-
bers as to attract general attention. When it does become
abundant grass land is stripped entirely of the green leaves
and the insects travel into adjacent fields to complete their
growth. They travel in immense hordes and devour all
vegetation as they go. Normally they are grass feeders and
are found in pastures and meadows and only when they are
unusually abundant do they migrate into other crops — wheat,

228

LEPIDOPTERA

oats, corn, etc., when they may occasion considerable loss.
In oat and wheat fields the>' may simply cut off the heads.
The life-cycle of the species is somewhat varied. It has heen
reported as passing the winter in various stages — egg, larv?e
and pu})iTe. The moths appear in the summer and eggs are
deposited in late summer or in autumn and probably a good
many of the individuals pass the winter in the egg stage.
Others become practically grown and then secrete themselves

Fk;. 178.— The ai

Hvliiipliila unipiiiictii) : «, full-ffrown

vvDiiu ynciiupiKiii uiti piuu in ) : (i, iuu-}z;ii>" ii army
vorm; b, enlarged view of front of head; c, parent moth; d, eggs in natural
position on grass leaf; e, pupa; c, d, e, about natural size; a, enlarged
about one-third. (Rearranged after Chittenden, Bull. 29, Div. Ent., and
Conistock, Report nf I'. S. Ent. for INTO.)

under the surface of the ground and hibernate. Others may
reach pupal stage and still others may reach adult stage
before winter. The great majority of the larval forms reach
their matiu-ity during May and June, and the greatest
devastation usually occurs during the latter part of June
and early July. Eggs are always laid in grass land and the
larva? begin their growth in the grass. One brood is
apparently the rule throughout the northern Ignited States,
and the difference in the stages obser\e(l diu'ing the year

NOCTUIDM 229

are due to irregularities and not to the appearance of more
than one brood. The insect is rather hard to treat economi-
cally because of its ordinary grass-feeding habit. When
the enormous increase in numbers occurs, the time for check-
ing them is really past. Something can be done for treat-
ment. One way is to use trenching methods for capturing
the larva?" as they travel over grass land — trenches put
across their line of travel and in this way large numbers
ma}' be captured and destroyed. It is also possible to spray
the grass in the line of their march with arsenical solutions.
These should not be used to pasture stock until the poison
has had time to be washed out and no harm will be done.
The trenches serve to prevent also the migration into wheat
and corn or oat fields if adopted early enough. The species
is parasitized quite extensively and when they become
abundant the parasites also increase rapidly. Their increase
is greater than that of the army worm. In this way there is
a great check of the army worm. One of the most important
of these parasites is the tachina fly which is closely related
to the house fly, blow fly, etc. There are other parasites
which are quite valuable also.

Cut Worms. — The species known generally as cut worms
are distributed through several genera and there are a
great many species that occur in pastures and meadows,
corn lands, and cotton, some of them are very abundant and
destructive and some may be considered as annual pests.
They usually live primarily upon grass and in the early
spring migrate into gardens and cultivated ground, where
their destruction becomes very evident. One of the most
im])ortant preventives is attention to grass land in autumn
adjacent to or upon the area that is to be planted in garden
or field crops. Tomato plants may be protected by tin
cans, or metal strips bent into cylinders and placed around
the plants and the cut worms may be killed by distributing
bunches of poisoned clover among the plants to be i)rotecte(l.
Some of the species are also attracted to light, and captures
of the adults will serve some ])ur])ose in reducing the numbers.
A feature of the work of cut worms not usually recognized

230 LEPIDOPTERA

is the regular loss in grass lands. In autumn and spring
they feed on the grass plants and destroy a much larger
amount of the growth of the grass than just what they eat
themselves. They cut oft' the grass and it withers and is
lost for either pasture or hay. The plant goes on growing
and the injury is often unnoticed by the cultivator even
where the cut worms occur by the thousands and tlie pasture
lands must suft'er a great deal of loss.

The life history varies a little in dift'erent groups but most
of the species that are troublesome occur in the adult stage
in midsummer, depositing eggs which hatch in early autumn,
and the larvse become practically grown and form little
cells in the earth where they hibernate through the winter
and issue in the spring and feed upon spring vegetation.
Then they pupate in the ground in earthen cells and issue
as adults in midsummer, any time from the first of June
to the first of August. Difterent species may occur at dift'er-
ent dates and in some cases it is important to determine
the exact time of appearance for the particular species.

Tussock Moths. — The tussock moths come in a different
family and one species wdiich is widely distributed is the
white-marked tussock moth {Notolophus leiicostigma). It
is pretty troublesome in orchards and on shade trees, and
occurs through the eastern United States and west to the
plains region. The larvae drop oft' from shade trees on the
sidewalks and on people who pass beneath. The larva is
the most conspicuous form and much more beautiful than
the adult. It is about two inches in length with rather bright
yellow markings along the sides and with conspicuous tufts
of yellowish hairs on the back and three quite conspicuous
long black pencils of hairs, two near the head and one on the
tail end, several red spots and numerous wdiitish hairs.
This larva when mature constructs a rather loose cocoon
and pupates during midsummer and early autumn and in
some cases the moths issue in a few days, in other cases not
until the following spring. There are two broods in most
cases, in others only one. In the case of two broods, those
that appear late in the summer deposit eggs which hatch

TUSSOCK MOTHS 231

and the larvse pupate and the moths appear late in the
autumn. There is ahvays an autumn deposition of eggs.
The females are wingless and the males are winged with plu-

179. — White-marked tusauek moth (Nololophus leucosligma) : larva
forming cocoon. (Photo by Ohio Exp. Sta.)

mose antennse. They are gray in color. The females crawl
out of the cocoon and do not leave it. After mating the eggs
are deposited on the surface of the cocoon. They make a

232 LEPIDOFTERA

large white mass, the eggs being inchided in a frothy sub-
stance which hardens and forms a varnish-hke coating
whicli ghies them to the cocoon and protects them tln-ough
the winter. The eggs hatch in hite spring or early summer
and the larvje grow, i)assing through several moults and
reaching maturity in midsummer or perhaps a little late
in sunnner. This is an insect that is single-brooded in a
Northern locality but may easily become double-brooded in
a Southern locality. This species is one for which the means
of control may be readily seen. P]gg masses are quite con-
spicuous in the winter and it is an easy matter to gather
these in the winter or late fall or early spring, and to destroy
them by burning or crushing. The insect's eggs are fre-
quently parasitized by minute hymenopterous parasites
which lay eggs in the eggs of the tussock moths. These can
be allowed to mature and pro\ide another generation of
parasites b\- putting the eggs where there is no vegetation.
The parasites when matured escape and the larva? of the
moths from unparasitized eggs will die.

Gipsy Moth. — Closely related is the Gipsy moth {Porthet-
ria (lispar), an important species from Europe. It was
introduced about forty-five years ago (1868 or 1869) and its
importation was for experimental purposes and not with
malicious intent. Eggs or possibly larvae may have been
blown out of an open window and the species thus given its
freedom. It did not attract much attention for several
years. It became abundant near Maiden, ]\Iass., and in the
early nineties became quite destructive and attempts were
made to exterminate it. In 1898, when its range had been

LEGEND FOR PLATE.

Gypsy moth (Porthetria dispar, Linn). (After Massachusetts State
Board of Agriculture.)
1, female with wings expanded; 2, female in resting position; 3, male
with wings expanded; 4. male in resting position; 5, pupa; 6, dorsal view
of one of the larger caterpillars, presumably a female; 7, dorsal view of one
of the smaller full-grown caterpillars, presumably a male; 8, egg cluster
on a piece of bark; 9, a few eggs greatly enlarged; 10, one egg still more
enlarged. '

.1

V

i

•^

>»'. #""

GIPSY AND BROWN-TAILED MOTHS 233

much restricted, the State discontinued its efforts, and in a
few years it had spread over a large area and its extermina-
tion was deemed impossible. A few years later wState and
National efforts for control were inaugurated and have been
pushetl vigorously in several different ways. The species has
caused great losses, and both State and National govern-
ments have spent great sums in attem])ting to keep it from
spreading and increasing.

The life history of the species is an important factor in
control. The moths appear in midsummer and autumn and
the males and females differ in appearance but l)oth ha\'e
wings, though those of the female are weak and their flight
is limited. Distribution of the species by the flight of the
females seems to be almost nothing, and the spread of the
species is mainly by the distribution of caterpillars. The
eggs are deposited in late summer and the egg masses sur-
vive the winter attached to trees, bark, etc. They hatch
in spring or early summer and the larvae make their growth
during the early summer months. They may be so numerous
as to almost completely strip the foliage of plants. At such
times the caterpillars make every effort to scatter, attach-
ing themselves to vehicles, etc. There are se\eral parasites
for the species, but none which are distinctly effective in
this country in keeping the species down. Different methods
adopted by the Massachusetts Commission are extremely
interesting. A volume has been published on the Gipsy
moth. Spraying, burning, scraping of trunks of trees, etc.,
have all })een used. In one instance every inch of an
immense elm tree was gone over. Extended efforts ha\'e been
made to introduce parasites and predaceous enemies to aid
in control of the species.

Brown-tailed Moth. — Another species of rather recent
introduction is the brown-tailed moth which was first
observed in Massachusetts in the ^dcinity of Boston about
the year 1890 or 1891. This is a native of central Europe
and is particularly common in France and Germany where
it is recognized as a destructive species. The female flies
readily, and thus it has spread more rapidly than the Gipsy

234 LEPIDOPTERA

moth, and now occurs throughout the eastern part of Mas-
sachusetts, New Hampshire, and eastward into New Bruns-
wick and Nova Scotia, south and west into Connecticut.
It is quite certain to spread by degrees throughout a large
part of the entire forested portion of North America. The
aduhs are white with the hinder portion of the abdomen
brown. The eggs are kiid on trees in small clusters and ha\'e
a brown appearance. The larvse hatch in early autumn and
the caterpillars become about half-grown before winter and
then spinning up in clusters, form a nest of leaves and web
in which they secrete themselves for the winter. In spring
with the opening of foliage they wander from these nests,
attacking the foliage and causing serious injury, completely
stripping the trees, so that they may be killed especially if
the attack is repeated for two or three seasons. The larvae
complete their growth by early summer, pupate, and pro-
duce moths in late summer, thus completing the annual cycle.
The larvee feed exposed on the foliage and may be killed by the
arsenical sprays when occurring on orchard or shade trees,
where it is possible to reach them with the spraying machin-
ery. An evident means of control is to destroy the over-
wintering insects during fall, winter or early spring when
they should be conspicuous on leafless trees. They are
easily shipped from place to place on twigs or small trees
and should be excluded by inspection of shrubs, trees, or
cuttings that are imported.

While not at present established as pests outside of the
New England States, these insects deserve to be watched
and particular pains taken to prevent their dispersal. Such
watchfulness may serve to greatly retard the distribution
and postpone the time when they may be destructive in any
particular region.

Web-worm Moths. — The web-worm moths are little, white,
with femur of front legs of yellow or orange tint, and the
legs and feet with little touches of black. These moths are
plentiful during the summer — about the last of June. They
deposit eggs in masses on the under surface of the leaf.
When the young hatch they usually first attack the leaves

TENT CATERPILLAR

235

on which the eggs were deposited, enclosing it in a web and
tJie whole colony begins to feed on a single leaf adjacent
to it. After the first moult they pass to other leaves and
include large numbers of leaves and sometimes the whole
tree. The entire colony feeds within the silken web. None
of them go away to scatter over the tree. There are several
moults, about five. They pupate a little later in the season
and the adults issue in the following spring. Two broods
are known in some localities. It is a great pest in orchards

p:X f-'^^^J

Fig. 180. — The fall well worm {Hyphantria cunea) : o, dark larva from
side; 6, light larva from above; c, dark larva from above; rf, pupa, ventral
view; e, pupa from side; /. adult. All slightly enlarged. (After Riley.)

and occurs on more than one hundred kinds of plants. The
web worms are so conspicuous that there is little excuse for
neglecting them and clipping off the newly formed web
with the end of the twig infested, or crushing or burning the
colony is so simple a matter that no one should permit
them to multiply.

Tent Caterpillar (Clisiocampa amcricona). — This is some-
times called the American tent caterpillar. The Western form
is called the Western tent caterpillar. They are more com-

236 LEPIDOPTERA

mon in orchards than in forests. Hiey differ from the fall
web worm both in life history and in the character of the
tent or web and in the habits of the larvte. The a<lnlts are
heavy-bodied and hairy, with long slender scales. They

(Photo by Ohio

TENT CATERPILLAR

237

appear rather early in the autumn, depositinji; masses of
eggs in eircles around the twigs, usually eompletely encircling
the twig. The eggs are glued together very firmly with a
varnish-like substance that covers and protects them for
the winter season. The largest part of the time is spent in
the egg stage, that is, through autumn and winter and

Fig. 182.— Webs of fall wel) \v..rin ( H ij phantria cunca) (,ii defoliated
walnut tree. (Photo by author.)

through early spring. The eggs hatch quite early, about
the time the foliage expands or a little in advance of the
foliage, and the larvjie construct a nest generally in a crotch
of a rather fair-sized branch — perhaps an inch and a half
in diameter. The web fits into the crotch and extends out
beyond it. The web is not much increased after first formed.
The lar\'te scatter when feeding on the lea\'es and retire to

238

LEI'IDOPTERA

the tent for protection when not feeding. In this they (Hffer
from the fall web worm. They have fairly distinct times of
feeding and of resting, the feeding being perhaps more com-
monly done in the early, cooler part of the day, perhaps more
or less at night, and protection in the web being sought in
the middle of the day or the hottest portion. They get their
growth pretty rapidly, requiring only a few weeks in early
spring for their development, and then they scatter mainly

Fig. 183. — Stages of the apple-tree tent caterpillar: a, egg mass; b,
larva; c, pupa; d, cocoon; }, female moth; ,r, male moth. About
natural size. (After Quaintance, Div. Ent., U. S. Dept. Ag.)

from the nest and construct cocoons in all sorts of protected
places, under bark, under boards, on fence posts, under
ground, etc. The cocoon is rather irregular, not very com-
pact and within the cocoon they change to pupae. This
pupation or change to the pupal stage takes place soon after
the cocoon is formed. They remain in the pupal stage only
about three weeks and then issue as moths, coming out in
the summer. They do a great deal of damage which is rather
more pronounced because of the early attack on the foliage

Fig. 184. — Apple-tree caterpillars (Mafacosoma americana) and "nest;"
egg mass or belt on small twig at left. "Nest" considerably reduced;
caterpillars one-half natural size. (After Quaintance, Div. Ent., U. S.
Dept. Ag.)

(239)

240 LEPIDOPTERA

before it is fully expanded. A single nest may serve to
defoliate an entire tree of ordinary size. The method of
destroying them will be a little different from that of the
fall web worm on account of the habit of scattering oxgv the
tree. To kill the entire colony it is necessary to take the
time they are all in the nest, when they can be destroyed
as easily as the fall web worm. The best way is to destroy
the egg masses. The egg masses are conspicuous enough to
be readily seen and by destroying them the injury for the
following season can be prevented. They are readily con-
trolled in this manner. When foliage is on the tree the
egg masses are not so readily seen. A little attention for
a year or two will practically rid an orchard of these pests.
They are heavy^bodied and although winged, do not travel
far. The moths are a dark gray or slightly rusty brown
and are much like a number of other moths. Two light bands
extend across the wing a little obliquely to the axis of the
wing. These are bordered by a slightly darker stripe.

The forest tent caterpillar is very similar in the appearance
of the larvse and in the building of the tent but differ in the
egg masses. The eggs stand straight out; and this species
is not so important as the tent caterpillar.

The Cecropia moth, Luna and American silk worm are also
quite prominent, but are not as ini])ortant economically
as the preceding species. All are silk-making forms, but
their silk production does nc^t compare' with that of the
Chinese worm. The silk worm is the most important insect
considered from a stand-point of producing an important
product — the honey bee is the only other of great impor-
tance. The silk industry will perhaps come into greater
prominence in this country if labor is cheaper or there is a
larger class of unemployed, as it requires a great deal of
attention but no great skill of labor. Too much time and
trouble are necessary to rear silk worms profitably in a greater
part of the United States. In France, Italy, China, and
Japan it is a very large industry.

This finishes what are known as the moths proper — the
Lepidoptera which liave antennae without any knob at the
end and which are almost all night-flying.

PAPILIONID.E

241

The next group are day-flying, butterflies, etc., and have
a difl'erent form of antennae. The skippers are somewhat
intermediate. Their antennae are slender and run out.
sometimes into a hook, or end in a thread-hke structure.
The butterflies ha\'e a thickening at the tip of the antennae.
Butterflies are strictl\' diurnal and are contained within
four or five distinct families. Hesperidae are intermediate
not only in these antennae but also in the wings. In the

Fig. 185. — Cecropia moth, larva; natural size. (Photo. Ohio Exp. Sta.)

butterflies the wings are folded up vertically over the back.
In Hesperidae they are about half and half. Some fly at
twilight — the yucca-borer — others in the daytime.

Superfamily Pajnlionidce includes the swallow-tailed
family. There is a tail-like appendage on the hindwings,
which varies considerably in different species. The larvae
are most of them characterized by the presence of peculiar
fleshy organs which are projected from the segment behind
16

242 LEPIDOPTERA

the head. This flesliy organ is thrown out when they are
irritated. It gives off a very pecuHar odor characterized by
some as hke the flavor of ripe peaches. This is presumably a
protective device. The caterpillars are many of them
banded distinctly and others have rather neutral colors and
eye-like spots on the body. A large black form with yellow
stripes on the wings is one of the most common here. In the
South it feeds on the orange and is known as the orange dog.
In Northern localities it feeds on the prickly ash and the
pawpaw. The caterpillar of this species, Papilio cresphontes,
has much the appearance of the excrement of birds. In most
of the Northern vStates the species is rather rare, but in the
South is quite abundant.

Pieris rapse, in the family Pieridw, is the common cabbage
W'Orm or cabbage butterfly. This species was introduced
from Europe into America some forty or fifty years ago,
probably in the vicinity of Quebec, and has spread over all
the eastern United States and practically over all the country.
Its life-cycle is pretty definite and the broods are pretty well
marked, there being two broods each year. Starting with
the adults that appear in spring or early summer, eggs are
laid on cabbage or other cruciferous plants and after hatching
from the eggs, the larvae develop by midsummer and adults
of this generation lay eggs that hatch the latter part of
July or in August and develop during August and September
or October. This brood feeds particularly on the cabbage
heads which may be tunneled through quite well into the
interior or at least well through the outer leaves, damaging
them for use. The larvje are green in color and well protected
either outside or inside of the leaves. The larN'?e develop
through autiunn and mature by cold weather by the time
that the plants give out and then change to pupa^, the
chrysalids being formed in fence corners, sides of buildings,
and other protected places. Sometimes they get into build-
ings and sometimes simply under rubbish. They are likely
to travel considerable distances from the plants on which
they have fed. They pass the winter in this stage and the
butterflies issue in spring and deposit eggs for the first brood

ALFALFA CATERPILLAR 243

of larvae upon any of the crucifers available. Early cab-
bages may be attacked, the larvse feeding simply on the
leaves. Eggs are commonly deposited on wild mustard, etc.,
anfl the larvie develop on these plants. The pupal stage for
the first brood is quite short, about two weeks to twelve
days. There is enough variation in the time of appearance,
so that the butterflies may be present for three or four weeks
in both spring and summer, and so they are to be found
pretty well through the summer months up to the middle of
August or the first of September. The great bulk of them
come at about the time vegetation is opening up and again
about the first of August. The species is not very easily
controlled. It lives on a variety of food plants and is two-
brooded and this helps in sustaining it. If the first brood
could be destroyed it might be controlled, but it is hard to
do this. Trap crops may be planted, as mustard, etc.,
and then the entire crop destroyed after the eggs are deposited
on it. Butterflies can be captured while depositing eggs, a
cheaper method than applying insecticide. Remedies can
be applied to the cabbages, especially before they have
headed without any danger to the eating of the cabbages
after they have grown. It should be done with precaution,
especially after the cabbages have reached some size. If the
solution is the right strength, there is practically no danger,
as twenty-eight cabbages would have to be eaten at one meal
to poison a person. The best way is to apply poison before
the cabbages are headed out. If the treatment is pretty
thorough for the first brood and the early part of the second,
the effect will be pretty successful. Gathering of the pupa;
is possible, but is not practicable on a large scale. It is
better not to destroy these, but to pass them into a receptacle
with a wire screen so that the parasites may escape while
the butterflies do not. The parasites are sometimes abun-
dant and greatly reduce the numbers and in some seasons
render the use of remedies unnecessary.

Alfalfa Caterpillar {Eurymus eiiryihcme) .- — The alfalfa
caterpillar is a common species over most of the United
States and has attracted attention as a serious pest in the

244

LEPIDOPTERA

alfalfa-growing districts of the West and Sonthvvest. In the
Eastern States it is less abundant but still plentiful enough,

Fig. 1S6. — The alfalfa caterpillar {Eunjinus curythcme): female in the
adult or butterfly stage. One-half enlarged. (After Wildormuth, Bur.
Ent., U. S. Dept. Ag., Fig. 2.)

Fig. 187. — The alfalfa caterpillar (Eurymus eurytheme) : male in the adult
or butterfly stage. One-half enlarged. (After Wildermuth, Bur. Ent., U.
S. Dept. Ag., Fig. 3.)

so that it must have an effect on the clover crop on which
the larva feeds.

MONARCH BUTTERFLY

245

In the Eastern Mississippi Valley and Atlantic Coast
States it is perhaps less common than the related sulphur
butterfly, Colias jMlodke, which is so plentiful as adults
that it is fair to assume an abundant progeny feeding in
clover fields.

r^^

ii

Fig. 188 Fig. 189

Fig. 188. — The alfalfa caterpillar: egg — greatly enlarged. (After Wilder-
muth redrawn from Soudder, Bur. Ent., U. S. Dept. Ag., Fig. 4.)

Fig. 189. — The alfalfa caterpillar (Eurymus eurijtheme) : larva or cater-
pillar stage — about twice natural size. (After Wildermuth, Bur. Ent., U.
S. Dept. Ag., Fig. 1.)

Fig. 190. — -The alfalfa caterpillar (Eurymus euryiheme) : pupa or chrys-
alis stage — twice natural size. (After Wildermuth, Bur. Ent., U. S. Dept.
Ag., Fig. 5.)

Monarch Butterfly (Anosia j^kxippns) . — The monarch but-
terfly (family Danaidce) is interesting in two or three ways,
though not of any special importance economically. It is
one of the largest butterflies outside of the Papilios, and it

246 LEPIDOPTERA

is pretty readily recognized by the dark reddisli-brown color
with black bands and stripings and the border including a
number of white spots. It deposits eggs on milkweed as its
host plant. These eggs hatch very shortly and the larvae
develop during the latter part of the summer and ])U})ate
and become aflults in autumn, and it is quite common in
October to see immense swarms of these butterflies. They
gather along hedge rows and on trees, sometimes appearing
by millions. Late in the afternoon they will cluster on the
branches in immense numbers. At the time of their gather-
ing in immense numbers they seem to have a general south-
erly movement and they are known to migrate at least to
some extent during the autumn, though the migrations
probably do not cover as long distances as that of birds —
not over 200 to 500 miles. They appear in great abundance
in the South in the winter. It is not possible to follow indi-
viduals for very great distances, but evidently they hibernate
in the adult stage in the South and it is pretty generally
believed that the hibernating individua,ls in Northern locali-
ties are likely to perish. Individuals that start the first
generation must have travelled from the South. The spring
individuals are frayed and give evidence of having travelled
some distance. The spring-appearing individuals deposit
eggs and from these the generation of caterpillars comes
that mature during midsummer. The adults appear in the
latitude of New York about the middle or last of July.
There are tw^o distinct generations for each year. The cater-
pillar is quite prominently banded and has some striking
thread-like appendages. It reaches the length of one and a
half or two inches and is nearly as thick as a pencil. It is
found particularly on the milkweed. Their pupation occurs
by attachment to the leaves of the milkweed or plants or
objects convenient or adjacent to the host plant. The pupa
cases are attached by a sort of spur or hook at the posterior
end of the body caught into a little web that has been spun
on the leaf. The larxjie locate on a suitable object and spin
a little web and then the larva contracts and the larval skin
splits along the back and this larval skin is held l)y the pos-

NYMPHALID^ 247

terior segment in such way that it can twist the pupa case
around and catch the hook of the pupa case into the web.
The pupa case hxsts only a week or ten days and then gives
rise to the adult form. It is mimicked by a species which has
an additional black band on the hind wing and there are
differences in the legs. This, the viceroy (Basilarchia
archipjms) has evidently gained protection by taking on
the appearance of the monarch.

One other species in the family Nymphalidce that should
be noticed is the common mourning cloak vanessa (Euvan-
essa antioya) which is interesting because of its very wide
distribution and its very great hardihood. It is said to occur
over practically all of the northern hemisphere from 30° to
the Arctic Circle. It occurs here in the winter time, hiber-
nating as an adult and has been found secreted in hollow
logs, bridges, and in almost any sheltered place, and if
taken indoors will revive and feed on sweetened water
quite readily. They begin to fly quite early in the spring.
It is double-brooded — the eggs deposited in early spring
produce larvae which mature in midsummer. They breed
on willow particularly and the larvae are dark-colored and
rather conspicuous. They also infest poplar, elm, and
dogwood, but willow seems to be the favorite. The chrysalis
is attached to the twigs of these plants and the adults
appear in midsummer. These adults deposit eggs and a
second generation appears in autumn which hibernates and
carries the species o^•er winter. In some places they have
an economic importance, but ordinarily they are not a
serious pest, and the butterfly is such a handsome species
that it may be counted as deserving immunity.

CHAPTjER IX.
ORDER DIPTERA.

This is a \ery large and important order and includes a
number of important economic species such as the house
fly and the mosquito. They are separated from all other
insects by the wing structure, the front wings only being
fully developed as means of flight and the second wings
being modified into knob-like structures which seem to have
some use in sustaining the insect in a certain position.
They vibrate but cannot serve any distinct function as a
means of flight. They are modified wings. This is a case of
specialization, reduction in size. This is coordinated with
the centralization of the nervous system. There is distinct
metamorphosis whose stages are usually sharply marked.
The larva? are usually called maggots, those of the mosquitoes
"wrigglers." The larvae occur in all manner of situations.
Some are aquatic, some terrestrial, some subterranean, etc.
The group is separated mainly by larval characters — one
group including mosquitoes and gnats, another the more
specialized flies. The larva contracts and the skin hardens
and forms a pupal case whose end splits oft' like a cap.

The Orthorapha, mosquitoes and gnats, are the less
specialized or the more primitive group.

Of the groups in the first series the mosquitoes (CulkidcB)
are the most in evidence, if not the most important, and
are receiving more attention lately because of their asso-
ciation with the transmission of various diseases. The
mosquito is not a single species. There are a great many
dift'erent species and they differ a great deal in life history
and habits and in their relation to disease. The most general
statement to be made regarding their cycle is that the eggs
(248)

MOSQUITOES

249

are deposited on the surface of the water and perhaps in
some species in mud or damp earth. The larvse are essentially

Fig. 191. — Anopheles maculipennis: male. Fig. 192. — Anopheles maculi-

Carrier of malaria. (Harrington.) pennis: female. Carrier of

malaria. (Harrington.)

Fig. 193. — Anopheles punctipennis: male.
Howard.)

Carrier of malaria. (After

250

ORDER DIPTERA

aquatic and air-breathing, with tlie trachea opening at the
end of the abdomen. The pupae are also aquatic but keep
near the surface and spiracles open near the head. The pupa
case splits on the dorsal side and the mosquito rests on the

Fig. 194. — Anopheles punctipennis: female. (From Howard,
Div. Eiit., U. S. Dept. Ag.)

surface of the water until its wings are dried enough for flight.
One species has been observed whose eggs may remain over
winter in mud, and hatching and development depends upon
the presence of water. Mosquitoes breed in minute quanti-

MOSQUITOES

251

ties of water if they have it for a few days, and especially
those that are more common about towns depend on small
pools, tanks, and rain barrels rather than larger bodies of
water. More breed in small pools than large, because there
are usually no fishes in the small pools. They fly for a few
rods ])ut for no extreme distance — one-half mile or a mile.

Fig. 195. — Culex taniorhynchus: female showing the short palpi which
distinguish Culex from Anopheles; toothed front tarsal claw at right —
enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.)

They may be transported, but most annoyance comes from
those bred close at hand. The connection between mosqui-
toes and malaria has been fully established. The parasite
seems to be dependent upon two distinct hosts. Unless
there is a case of malaria in the near vicinity they cannot
communicate it to another. The relation of mosquitoes to
yellow fever has also been worked out very carefully. One

252

ORDER DIPTERA

Fig. 196. — Resting positions of Culex (at left) and Anopheles (at right) —
enlarged. (Redrawn from a rough sketch published in the British Medical
Journal.) (From Howard, Div. Ent., U. S. Dept. Ag.)

Fig. 197. — Yellow-fever mosquito (5^effom!;ja /a.scioia) : ^.niale; B,
female. (After Howard.)

GALL GNATS 253

striking thing is the discovery of the immense nmiiber of
species of mosquitoes. There have been many new species
discovered in the last few years.

Gnats {Chironomidoe) . — Gnats are related to mosquitoes
and are interesting partly because of their close resemblance
to mosquitoes and partly because they occasionally multiply
so as to cause annoying contamination of reservoirs or
obstruction in water tanks. The antenna? are plumose as
in the mosquitoes but the mouth parts are different. The
larva? are more distinctly aquatic than the mosquito larvae —
can survive down in the water without coming to the sur-
face for air. Some live in mud — slender red, worm-like crea-
tures. One species is quite plentiful in the Northern States
especiallv near lakes and sometimes as abundant as the May
flies.

Gall Gnats. — The next group is the one including the gall
gnats. It is a very important family with two or three very
important species. The most conspicuous of the galls
{)r()(luced by these is the cone gall produced on willow trees —
the pine cone willow galls. These are the result of the work
of the lar\'0e of the gall gnats. They are made up of a series
of leaves which o^'e^lap in the form of a pine cone. These
correspond with the leaves that would have come out along
the twig had it grown out normally. The leaves are devel-
oped close together and the larNje of the gall gnat is found
in a little cell in the centre of the gall. It issues in the spring
and deposits its eggs in the willow buds before the twigs
have started to grow, and the larvse hatch and form the galls
by feeding. There are a good many things in these galls
besides these larvae. Other insects find them a convenient
shelter, and other insects deposit eggs there. The tree
crickets are an example of this. These may be a little mis-
leading but they have nothing to do with the formation of
the gall. The pine cone gall is most conspicuous. There
is another species which simply produces an aborted growth
that looks like Brussels sprouts.

The other species in this family to be mentioned are the
clover and wheat midges and the Hessian fl}'.

254

ORDER DIPTERA

Clover-flower Midge {T>asynenra leguminicola). — The clover-
flower inid^e li\es within the heads of clover and feeds U])on
the clover bloom and seed. Its life-cycle is adapted to the

/ '% <iC>(Sf

Fig. 198. — The rlover-flower midge (Dasyneura leguminicola) : a, enlarged
dorsal view of male with scales denuded; b, head; c, genitalia; d, antennal
joints, more highly magnified, to show structure; e, tarsal claw; /, /, forms
of scales. (From Riley, Div. Eut., U. S. Dept. Ag.)

l)looming of the clover, so that the larvae appear at the ])roper
time for feeding upon the clover seed. There are two fairly
distinct broods each season, the first brood of larvji^ develop

HESSIAN FLY 255

in early summer and mature in midsummer, tlie larvae issuing
from the clover heads and pupating in the ground anfl the
second brood appearing later in the summer and depositing
eggs which produce the second generation of larvae which
develop in the later blooming clover. These hit the crop
of clover grown for seed. They mature with the late autumn
and either maggots or the mature puparia would be found
during the winter time and the larvse particularly which are
caught before they have completed their growth may be
included in clover seed. The fully de\^eIoped larvae pass
into the pupa stage at the surface of the ground. It is
doubtful if the midge can be transported from one place to
another by means of the clover seed. Just how it is intro-
ducefl into remote districts is uncertain. Its means of loco-
motion is by its own flight. It is pretty generally dispersed
throughout the portion of the country where clover is now
grown. The means of treatment would lie more in the
direction of cutting the clover at the time to cut short the
growth of the larvae — a little earlier cutting of the clover,
catching the larvae before they have issued from the clover
heads.

Hessian Fly (Mayetiola destructor). — The Hessian fly is
the most destructive of the family. It is an introduced
species and was first described from materials. in this country
in 1820, It probably originated where wheat did. It was
never described scientifically until by Say. It had been
known as a destructive insect earlier than 1820 anrl the
name was given to it about the time of the Revolution, when
the Hessian soldiers were in this country, either because the
insect was thought to have been introduced by them or as
an obnoxious name. The name was adopted over the entire
English-speaking world. The evidence that it is an old-
world species is from its food plants and that it spreads
from one centre. There are a number of other evidences.
Its natural food plants seem to be limited to wheat, rye, and
barley, though there is a question as to barley. It was
proved by a Frenchman that it does not occur on oats. At
one time it was thought to breed in various grasses, but later

256

ORDER DIPTERA

studies show that this was not the true Hessian fly. If any
attempts are made to control it by rotation of crops its
restriction of food plants should be well known. Its life-
qycle is qj^iite similar to that of the clover-flower midge and
it has become very distinctly adapted to the crop it infests.
Any great change in ordinary methods of raising wheat
would likely prove destructive to the insect. The winter is

199. — The Hessian fly {Mayeliola destructor): adult female — much
enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.)

passed in the flaxseed stage — the puparium stage. The
larval skin shrinks and forms a tough, dark brown covering
about the size and shape of a flaxseed. Within this there
is formed a real pupa that has the outline and features of the
adult insect. There is a distinct metamorphosis. These
hibernating puparia give rise in early spring to adult midges
that deposit eggs on the stems and leaves of wheat plants —

HESSIAN FLY 257

winter wheat. In spring wheat regions the flies appear
at about the time of the coming up of the wheat and deposit
eggs on it. There is not necessarily much (Hfl'erence in the
time and method of deposition except that those on winter
wheat are apt to be a httle higher on the stems and farther
from the ground. Tliese burrow into the stem in such a
way as to cause weakening of the stalk, which is apt to bend

Fiu. 2U0.— The Hessian Hy: iidult mule— much enlarged. (After
Marlatt, Div. Ent., U. S. Dci)t. Ag.)

and break as it approaches maturity and falls to the grountl,
so that it cannot be harvested. Sometimes only 1 or 2 per
cent, of the field will be infested and in other fields one-third
or one-half of the crop will be lost. As the wheat matures
the larvse mature and change to the flaxseed stage and
remain protected between the sheath and the stem of the
plants down near the ground. Sometimes they are high
17

258

ORDER DIPTERA

enough to be cut ojff and carried with the straw when the
wheat is harvested, but more commonly are left in the

Fig. 201. — Egg of Hessian fly — greatly en-
larged; section of leaf of wheat, at right,
showing eggs as usually deposited, less
enlarged. (After Webster, Div. Ent., U. S.
Dept. Ag.)

Fig. 202.— The Hess-
ian fly : larva before" flax-
seed" is formed — much
enlarged. (Webster, Div.
Ent.. U. S. Dept. Ag.)

Fig. 203.— The Hessian fly: larva
taken from "flaxseed," much enlarged
with "breast-bone" still more enlarged
at right. (After Webster, Div. Ent.,
U. S. Dept. Ag.)

Fig. 204 —The Hessian
fly: pupaiium or "flax-
seed," much enlarged.
(After Webster, Div.
Ent., U. S. Dept. Ag.)

stubble. They sur\'ive the midsummer in this condition and
are apparently dependent more or less on conditions of

HESSIAN FLY

259

temperature and moisture. They come out in the fall and
are ready to deposit eggs on wheat plants accessible in the

Fig. 205. — The Hessian fly: pupa taken from "flax.seed," greatly

eularjicd. (After Marlatt, Div. Eiit , U. S. Dept. A-.)

Fig. 206.— Injured plants and flaxseeds. (Photo by Ohio Exp. Sta.)

260 ORDER DIPTERA

autumn. The eggs deposited in the autumn give rise to larvae
whicli de\elop and pass into the flaxseed stage to hibernate.
If tliey are accelerated in their development and are provided
with food material — volunteer wheat — there may be one or
more extra broods in the summer. As high as five or six
extra broods were observed by Marchal. There are ordi-
narily two broods adjusted to the occurrence of young wheat
plants. One important thing is the distribution of the
species by means of the shipping of infested straw. This
must be the main or only means by which the species is
taken from one country to another. It has been introduced
into most wheat-growing countries of the world. The
natural distribution of the species is limited to about 20
miles a year. Flight aided by the wind might carry it some
little distance. For local measures attention to the stubble
is one of the most important things. If it is thick and dry
enough to burn over diu'ing midsummer, it can be destroyed
in this manner. Plowing under very deeply is another
method but must be done early enough to bury the stubble
before the flies have issued. T]je most generally practised
method, and most highly recommended, is to adjust the time
of planting so as to avoid the period of egg deposition. If
the time of planting wheat can be deferred for a week or two
after the appearance of the flies, it will escape. Flies will
not deposit eggs on the bare plowed field. If the wheat comes
up after the flies have issued and passed the egg-laying period,
it escapes attack. F'or the Central States the time of aj)pear-
ance has been pretty definitely determined, and it has been
shown at what time wheat can be planted with the greatest
security. For the latitude of Columbus, Ohio, it is about
the first of October. It is possible to plant trap crops so as
to catch the flies as they appear and the whole crop can be
plowed under after the eggs are deposited on it. This is not
particularly popular. If planting is done with reference
to temperature and to dift'erent seasons, results will be better.
Hot, dry weather seems to prevent the issuing of the flies.
Family Simuliidae. — The family Swudiidw includes the
black flies and buft'alo gnats. These constitute extremely

FAMILY SI MU LI I DM 261

injurious pests and occasion many losses to agriculturists,
so that they deserve a paragraph at this point, although for
most of their existence they have very little in common with
farm life. They have had an added interest in recent years
on account of the effort to prove them the carrier of the
disease known as pellagra, but proof of such a comiection
is still wanting. The adults are short, small, thick-lxxlied
insects; the thorax especially heav\', and the humped appear-
ance of the whole body has given rise to the name buffalo
gnats. They are all small species, scarcely any of them a
q-uarter of an inch in length. The larv?e are distinctly aquatic,
usually living in swiftly running water. They are so fully
adapted for aquatic life that they attach themselves by
silken threads to submerged objects and depend for their
food upon minute organisms floating or swimming in the
water. The pupal stage is also passed under water, a thin
cocoon being spun upon the under side of the leaf or other
submergcfl object. When the adults emerge from these they
rise rapidly to the surface of the w^ater, the wings expanding
promptly, and they are ready for flight almost instantly.
At times they occur in enormous swarms and the females
are very blood-thirsty, attacking all kinds of warm-blooded
animals, sometimes with very disastrous results. In the
Northeastern States and in parts of Canada, especially in
Labrador, there is a species known as the black fly. They
occur at times in such abundance as to make it practically
impossible to remain out of doors, and domestic animals will
seek any possible shelter in order to avoid the attacks of the
insect. In the Southern Mississippi Valley there are two
common species which have been studied in detail. One of
these, the turkey gnat, is said to make its attacks very gen-
erally upon poultry, although it is not limited to these animals.

The other species which is credited with the greatest
amount of loss in the Mississippi Valley region may be
considered somewhat in detail and as a representative for
the family.

Southern Buffalo Gnat {Simulium pevnarum, Kiley). — The
•investigations of 1885-86-87, which have been reported very

262

ORDER DIPTERA

fully in the Department publications, and from which the
statements here made are mostly compiled, have shown
that the extent of territory invaded by these insects is much
greater than formerly supposed. It may be stated to com-
prise, in the worst years, the whole of the Mississippi Valley
from the mouth of the Red River, in Louisiana, to St. Louis,
Mo. All the adjacent land to the many rivers and that
empty from the east and the west into the Mississippi River

Fig. 207. — Simuliiun pecuarum: larva — enlarged. (From .\nnu:
Report of Department of Agrioulture, 1886.)

is invaded by swarms. They are driven about by the wind
and reach points far away from their breeding places.

The extent of the losses due to this species has already
be«n stated, though it is, of course, impossible to separate the
losses due to this species from those caused by the turkey
gnat. Li a general way the latter may be said to be more
destructive to poultry, while the attacks of this species are
more particularly directed against the larger domestic
animals.

FAMILY SIMULIID^

263

The larva is not differeint in general appearance from that
of other species. The annexed cut (Fig. 207) shows it con-
siderably enlarged and will make a detailed description
unnecessary. It is translucent when living; the body in

Fig. 208. — Simuliurn pecuarum: head of larva: a, beneath; b, side;
c, above — greatly enlarged. (From Annual Report of Department of Agri-
culture. 1886.)

Fig. 209. — Simuliurn pecua-
rum: pupa — enlarged. (From
Riley.)

I'll:. 210. — Simuliuni pecua-
rum: female, side view — en-
hirtied. (U. S. Dept. Ag.)

some individuals is without markings, while in most it is
distinctly marked with dark cross bands on the back in the
middle of the joints, while at each side is a white space;
the under side is more or less irregularly spotted with brown.

264 ORDER DIPTERA

The liead is yellowish-brown, nearly square, horny, and
marked as in the figure (Fig. 208).

The tip of the abdomen is crowned with rows of hooks,
and on the up])er side of the abdomen is the set of breathing
organs, which have been mentioned heretofore.

The larvaj are fovmd more particularly attached to sub-
merged logs, wholly or partly submerged stumps, brush,
bushes, and other like objects in the larger creeks and bayous
of the region to which they are common.

B.-^*V ''l-'-rsf

Fig. 211. — Sirnulium pecuantm: head of m.'ile ;it riglit ; head of female
at left — greatly enlarged. (From Annual Report of Department of -Xgri-
culture, 1886.)

When fully grown the lar^•^e descend to near the bottom
of the stream, sometimes eight to ten feet, to make their
cocoons.

The cocoon upon these leaves is conical, grayish or brown-
ish, semitransparent, and has its upper half cut square off,
more or less ragged, as if left unfinished. Its shape is irregu-
lar, the threads composing it very coarse, and the meshes
rather open and ordinarily filled with mud. They are not
always fastened separately, but frequently crowded together,
not forming, however, such coral-like aggregations as in some
of the Northern species. The larva in spinning does not
leave its foothold, but running in the centre of its work, uses

FAMILY SIMULIIDJE 265

its mouth to spin this snug little house. In it, it changes to
;i pupa, which has its anterior end protruding above the rim.

They remain in the pupa state but a short time. Both
larval and pupal skins remain in the pouch for some time.

The adult fly on emergence from the plipa rises quickly to
the surface, and the wings expanding almost instantly, it
darts away.

The time of the appearance of the swarms is regulated by
the earliness or lateness of the spring, and consequently it
is much earlier in the southern parts of the Mississippi
Valley. As a rule they can be expected soon after the first
continuous warm weather in early spring. In 1S85 the first
swarms were observed in Louisiana March 11, in Mississippi
and Tennessee May 1, and in Indiana and Illinois May 12.

Horse Flies ( Tahanidoe). — Horse flies are pretty well known
and quite important economically. They cause annoyance
to domestic animals and to man. They are not credited with
carrying any disease, but seem to be well adapted to such a
performance. They are aquatic in the larval stages so far
as the larvae have been studied, and the larvse are carnivorous
and seem to feed on a variety of aquatic life, dead or alive.
They pass through pupa stages in the mud or deeper in the
marshes of pools and ponds. The adults are very active
and swift flying. The eyes occupy practically the whole
head and are composed, especially in the males, of an enor-
mous number of facets. The females are the biting members
of the family, having the mouth parts much more fully devel-
oped. The males live on plant juices, but probably do not
feed extensi^'ely in the adult stage. The females seem quite
blood-thirsty, though perhaps this is not a necessary food.
The eggs are deposited in little clusters or masses on aquatic
plants, usually just above the surface of the water, so that
the larvse on hatching at once enter the water. The insects
of this group are much more abundant where there is an
area of water surface to provide the w^ater habitat. The
females gather to the water probably to secure water in con-
nection with the deposition of the eggs, and a Russian ento-
mologist proposed the plan of putting kerosene on the surface

266

ORDER DIPTERA

of the pools to destroy the adult females, and this seems to
have been very successful. The trouble in this is that the
kereosene kills other forms of life which are not obnoxious.
There are several species in this locality. The species com-
mon about horses are the green heads and the big black flies.
The green heads sometimes cause a great deal of trouble.

The remaining families of the order come in the suborder
Cyclorhapha. This group includes an immense number of
flies, many different families and some of the families an
immense number of species.

Fig. 212.— Tabanus atratus.

larva; b, pupa; c, adult. (After Riley.)

The first important family in the group is that known as
the SyrphidoB. This one family presents about as great a
variety of life, habit and conditions as any in the order.
There is everything from aquatic to arboreal species in the
larvse. The rat-tailed forms which live in liquid have a long
tube extending to the surface of the liquid. Another species
occurs on trees. The more important economically are
the ones that feed on plant lice, and these are a most impor-
tant factor of control. Many species mimic members of
other groups of insects. Some look very much like wasps,

FAMILY OESTRIDM

267

others like bees, and the rat-tailed species {EriMcdls tcnax)
looks like a drone bee.

Bot Flies (Oestridcr). — The hot flies are parasitic in various
mammals, occupying the body tissues and primarily the ali-
mentary tract. The adults are bee-like, with rounded heads
and small eyes, and are hairy. The antennne are sunken into
little pockets or pits in the front of the head, and the mouth
parts are aborted. The adults do not feed. The females are

Fig. 213. — Horse bot fly (Gastrophilus equi): a, egg, enlarged; b, nat-
ural size; c, larva, newly hatched, enlarged; d, more enlarged: e. oral
hooks; /, body spines; fir, mature larva, twice natural size; h, adult female.
(Author's illustration. Bur. Ent., U. S. Dept. Ag.)

the more commonly seen and they deposit their eggs on the ani-
mals that are to serve as hosts for the larvte. The males gener-
ally remain in shady places among grass, etc., so that they are
much less likely to be observed. The larvje seem to have
adjusted themselves to the parasitic condition from a more
primitive condition, possibly that of living in organic matter
of some kind. It seems most likely that some form with
habits perhaps like the blow fly might in some cases deposit

268 ORDER DIPTERA

eggs in siK'li places that the larva? would survive and the
habit gradually acquired of living within the host tissues.
They reach maturity without destruction of the host form
and the habit gradually becomes fixed. This habit is now
definitely fixed among all the species of the family and
they are restricted to mammals as hosts. Some infest the
alimentary canal, some the nasal passages, some the tissue
beneath the skin. The larva; as parasites have undergone
consideral)le modification from the primitive forms. They
are usually pro^'ided with rows of spines or sharp spurs that
assist their movements when they leave the host forms and
for those that live in the alimentary canal there are hooks,
modifications of the mouth parts, that serve to attach them.
They may feed to some extent upon the secretion of the host,
})ut most of the nutrition is absorbed through the body walls.
The Horse bot fly {(i astro philus equi) is one of the best
examples and probably represents most nearly the primitive
condition for the family. The adult occurs through the middle
and last of summer and the eggs are deposited on the hairs of
the horse, small yellow eggs glued very firmly to the hairs.
In depositing the eggs the female darts toward the animal
and thrusts the egg against the hair without alighting. The
abdomen is thrust forward under the body. A glutinous
secretion is discharged with the egg and binds and hardens
almost immediately. The eggs are very thick-walled with
chitinous walls and have a little operculum or cap at the end
of the egg which is easily detached after a certain stage in
the development. The time for hatching varies from three
days to forty, but usually ten to fifteen days after deposition.
Before that time they are hatched with a great deal of diffi-
culty, and the larvae are rather inactive. After fifteen to
twenty days the activity begins to diminish. The majority
die if not hatched in thirty to forty days. They do not
hatch without the assistance of moisture, friction, and
warmth to stimulate the larvse. With a little moisture and
friction the cap slips off easily and the hooks of the larva
fit it to attach itself immediately to the tongue or other part
of the body of the horse. The egg shells remain on the hair

FAMILY OESTRID.E 269

after the hatching occurs. The time for the hatching of the
eggs is rather important with regard to the treatment of
the animaL It has been studied pretty carefully. Dif^'erent
statements as regards the period of incubation may mean
different species observed. Egg deposition may go on until
quite late in autumn, but is usually at its height about
August or early September. The activity is retarded by cold
weather and the larvae may survive longer then. The method
by which they get into the stomach of the horse is by the
horse licking itself or some other animal on which there are
eggs. At first they are long and slender but after attachment
in the stomach become thicker and fasten themselves by
hooks to the stomach and remain there through late autumn
and winter and early spring. They are sometimes very
thickly set in the stomach of the horses. They must cause
considerable interference with the activity of the stomach,
and if massed together at the pyloric orifice may act as an
obstruction. The effect on the animal is in some cases quite
evident. The damage is doubtless different in different
animals. The worst infested are those that have been in
pasture. When they have completed their growth in the
stomach they loosen their hold and pass out of the stomach.
They burrow into the ground and pupate and remain in this
condition several weeks — six or seven — and issue from mid-
summer to early autumn. There is one generation a year
and the longer period is spent in the body of the animal.

Treatment for the larvae is rather severe. They may be
killed with turpentine, but care must be used not to injure
the horse by an overdose. The means of prevention are
indicated by the life-cycle — condition of the egg and length
of time it may develop. If eggs are removed every week or
ten days there is no danger of serious infection. Horses
curried regularly are not apt to be infested. They may be
shaved off, and this is the most ready means of preventing
the infection. Washes could be used to kill the larvte —
kerosene, carbolic acid, etc.

There are three or four species of this parasitic genus in
the horse, but no other so common as Gastrophilus equi.

270

ORDER DIPTERA

They cause a good deal of annoyance. One is called the chin
fly (Gastrophilus nasalis), whicli lays eggs on the jaws.
Another, the red-tailed botfly (Gastrophilus Jiceniorrhoidalis),
also deposits eggs in the vicinity of the mouth.

Bot Fly of the Ox ( Ilypoderma lineaia).- — The hot fly of the
ox illustrates another method of development, but seems
to have been derived from that of the one occurring on the
horse. It is known in some parts of the country as the
Texas heel fly. It occasions a great deal of loss to the cattle

Fig. 214.— Hypodc

1 lincala: female — natural size
line. (From Insect Life.)

I ted by side

industry. The lar\;e perforate the hides. They develop
luidcr the skin and on maturing pass through the skin,
leaving a lot of openings. Such hides are docked one-third
in the market. Eggs are laid on the hairs of the legs, and as
he found none on the hairs of the back, Dr. Curtice concluded
that the larvae were taken into the mouth and travel by way
of the esophagus and through the tissues of the thoracic
region up through the tissues of the back as their normal
route. The puncture is made after the larva is under the

FAMILY OESTRID.E

271

Fig. 215. — Hypodcrma horis — enlarged. (After Brauer.)

Fig. 21G.— Piece of warbled hide—warble.s about half size. (After
Omerod.)

272

ORDER DIPTERA

skin and some time before it is ready to issue. The adults
appear quite early in the season and the larvae in the hacks
of cattle are never seen until in the winter time — January
first to March or April. They cause the muscles to have a
jelly-like consistency. They injure the cattle in regard to
growth and to milk conditions. The annoyance of the flies

■'

/•

' 1

i 1

I

/

\ 1 '

^ \ 4 '

Fig. 217. — Hypoderma lincata: a, eggs attached to hair; b, c, d, dorsal,
ventral, and lateral view of egg; e, embryonic or first larva, as seen in egg;
/, a, mouth parts of same enlarged; h, anal segments of same'still more
enlarged. (From Insect Life.)

when they deposit eggs and also the injury caused by their
presence in the back of the cattle is in England estimated
at about -15.00 a head. Eggs are attached to the hairs, and
the larvae, according to Curtice, pass into the mouth and
through the esophagus and through its walls into the adja-
cent tissue and migrate by slow degrees to the dorsal portion
of the body, finally reaching the subcutaneous tissue along

FAMILY OESTRIDAS

273

the backbone, about six or eight inches from it and between
the shoulders and the hips. The time of the appearance
in that location and the time when the larvae are taken into

Fig. 218.- — Hypoderma lineata: ovipositor of female: a, from side; h,
tip, from below — enlarged. (From Insect Life.)

a

Fig. 219. — Hypoderma lineata: second stage of larva from esophagus:
a, larva; b, enlargement of cephalic segments, end view; c, mouth parts;
d, enlarged end view of anal segment, showing spiracles and spines. (From
Insect Life.)
18

274

ORDER DIPT ERA

the mouth are separated by quite a period. Curtice claims
to have found larvae at all points between these two positions.
This cannot be purely accidental. More recently an Irish
investigator has reached the conclusion that the larvae bore
into the skin and migrate to the wall of the esophagus from
which point they travel to the position under the skin of the
back. The adults emerge in early sinnmer, in Texas as

Fig. 220. — Hypoderma Hneata: a, second stage of larva from back; b
and c, enlargement of extremities: d. ventral view of third stage with
details of extremities at e and /; g, dorsal view of mature larva with enlarge-
ments of anal spiracles at h; i, the same, lateral view. Natural size indi-
cated by side lines. (From Insect Life.)

early as May, in northern States May or Jime. The larvse
are pretty well grown by February, and by early ]\Iarch they
have practically reached maturity and the grubs issue
during March and early April, drop into the ground and
pupate and remain in this stage for five, six,, or seven weeks,
and the adults come on from ^lay to early June or the first
of July.

The European species which has now been studied with

FAMILY T AC HI N I DM 275

special reference to its mode of introduction is believed to
follow the same method, but Miss Ormerod persisted in the
belief that the eggs were deposited on the back and that the
larvffi bored through the skin, and claims to have seen chan-
nels through the skin througli which the lar\-ie tra\'elled. It
is not likely that there would be this difference in the two
species. This species causes a great deal of loss in the old
world. The one method available for controlling either of
these species is the destruction of larva? during the late
winter and early spring when they are conspicuous along
the back, and the method of extermination of the species
would be to have all animals examined and all the grubs found
destroyed. This is feasible theoretically, but impossible
practically. They do not migrate far, and any stock owner
can by close attention secure a large measure of immunity
for his own herd. Cooperation would secure a more extended
extermination.

Sheep Bot Fly {Oestrus ovis). — The sheep bot fly illustrates
another method of development. It deposits eggs or newly
hatched larvae in the nostrils of sheep and these work their
way up the passages. This entrance occurs during summer
time and the development of the larvse goes on through fall
and the larvae work their way back in spring and pupate in
the ground and the flies issue in midsummer. They cause
the greatest irritation and most serious symptoms occur
during the time the larvae are working themselves back.
The sheep sneeze, etc., and sometimes show a dizziness or
stagger. They may be cut out of the frontal sinuses but the
cost of the operation is too great for general use. Preven-
tion consists in avoiding the deposition of eggs in the nos-
trils, x^pplying tar to the noses is one method, and another
method is by furnishing plowed places or dusty places so that
the sheep can bm-y their noses when the flies try to deposit
eggs, or by giving the sheep a shed, as the flies are active
in the sun and not in the shade.

Family Tachinidse. — The family Tachinidce has a very
important economic position on account of the large number
of species that are parasitic upon destructive insects. The

276

ORDER DIPTERA

adults appear much like the house flies or the stable fly but
have usually numerous prominent bristles and spines, the
bristles (arista) of the antennae lack the fine hairs which are
characteristic of most of the Muscidae.

These insects show some very striking adaptations in their
parasitic life, some of the species depositing their eggs
directly upon the bodies of the caterpillars which are to be
the hosts of the larvse. The larv« on hatching bore at once
into the caterpillar and develo]) within its tissues. In cer-

FiG. 221. — Euphorocera claripennis, a parasite of the alfalfa caterpillar:
adult and enlarged antenna of same; puparium — enlarged. (From Howard,
Bur. Ent.. U. S. Dept. Ag.)

tain species the eggs are laid upon the leaves and depend
for their entrance to a host insect upon the leaf being eaten
by some herbivorous form and in this case it would se^m as
if there would be some chance of the eggs being crushed or
the lar\pe being destroyed in the process of swallowing. In
one rather remarkable form the eggs are evidently deposited
within the burrows of wasps which are stored with spiders.
The TachinidcB follow the wasps as they drag their victims
to the burrow and when the wasp enters they no doubt

FAMILY MUSCID^

277

deposit their eggs upon the spider, the larva feeding upon
the food intended for the wasp larva or possibly upon the
wasp larva itself.

The typical Muscid flies {MuscidoB), house fly, blow fly
screw-worm fly, all live in organic matter in a state of decay,
and all of them show very rapid rate of development, the
larvae acquiring their growth in a few days' time, though
longer time is usually passed in the pupa stage. The adults
may live for a long time. House flies, for example, conceal
themselves about houses and survive the winter, possibly
also as pupse, and deposit eggs which start the summer

Fig. 222. — Common house fly (Musca domestica) : puparium at left;
adult next; larva and enlarged parts at right. All enlarged. (After Howard,
Div. Ent., U. S. Dept. Ag.)

generations which follow each other with a great deal of
rapidity. Twelve to fifteen days is all that is required for
the complete cycle of many of the species. They are scaven-
gers and in this may be looked upon as beneficial. They
present also certain dangerous aspects as carriers of disease,
especially typhoid, and deserve all the opposition they are
receiving.

The screw-worm fly deposits eggs occasionally in the
nostrils of individuals, and in the case of wounds of animals
the larvae work into the living tissue. It causes losses in
cattle industry in the South.

278 ORDER DIPTERA

The house fly {Musca doDicstica) is perhaps the most
uni\ersal, and occurs wherever civihzation extends, and
presents an important feature in its possibilities of carrying
disease germs. One of the first cases estabhshing this con-

FiG. 223. — The common house fly: a, full-grown larva; b, one of its
anterior spiracles; c, antenna; d, hind end of body showing anal spiracles;
e, side view of head; /, head from above; g, head of young larva: h, eggs.
All enlarged. (From Howard, Div. Ent , U. S. Dept. Ag.)

nection was that determined during the Spanish-American
war, where the source of the typhoid was traced to house flies.
It is known to serve as a carrier for tuberculosis, dysentery
and other diseases. Flies breed in filth, especially horse
manure, the eggs requiring a few hours to hatch, the mag-

FAMILY MUSCID^ 279

gots from four to six days to grow, and pupation six to eiglit
days, so there may be many generations in a summer. Pro-
tection may be readily gained by community effort. Their
flight is sufficiently' restricted to make individual effort on
a farm well worth while, even if some nearby farms are neg-
lected.

Fig. 224. — The common house fly: a, pupa removed from puparium;
b, hind end of body of larva in second stage; c, anal spiracles of larva in
fiist stage. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.)

Horn Fly {Hcematobio serrata Rob.-Desv.).— In the intro-
duction and rapid spread of this insect we have an excellent
illustration of the importance of gi\ing attention to the
injurious insects of other countries and of taking all possible
means to prevent their importation.

The species in hand has been a common insect in Europe,
and with other members of the same genus recognized as a
troublesome insect, though apparently no careful study of its
life history has been made there.

280 ORDER DIPTERA

It was first noticed as troublesome to cattle in this country
in 1887, and while we cannot say with certainty just when
it was introduced, we may be pretty sure that it was during
the year 1886, or at most not earlier than 1885. It is even
possible that it may have been brought over in the spring of
1887, as its powers of reproduction are such that a few weeks
would suffice to make it a conspicuous pest in a limited
area.

Within two years from the time it was first recognized in
serious numbers it had become so numerous and had spread
over so large a region that it was made the subject of a
very careful and successful study by Messrs. Howard and
Marlatt of the Division of Entomology. The results of
these investigations were published in Insect Life (vol. ii, p.
93) and in the Annual Report of the Commissioner of Agri-
culture for 1889.

As to its introduction and spread in America, all accounts
agree in placing the first serious occurrence of this insect in
the vicinity of Philadelphia, and it appears probable that
it was at that port that the flies first landed.

From there as a centre it spread in all directions, though
at first mainly southward, and by 1889 it had covered most
of the State of New Jersey, portions of eastern Pennsylvania,
a considerable area in Maryland, and also a portion of
northern Virginia.

In 1891 it had been reported from New York, Ohio, Ken-
tucky, Georgia, Florida, and Mississippi, and in 1892 from
Connecticut, Massachusetts, Canada, Michigan, Indiana,
Iowa, Louisiana, and Texas.

The adults of the horn fly are about half as large as the
common house fly and very much like it in shape and color.
The accompanying figures will serve to distinguish it. The
larval stages are passed in from four to six days.

The pupa stage may last from five to eight or ten days, so
that the full time from egg deposition varies from ten to
seventeen days, estimated for the average as about two weeks.
As the flies doubtless begin laying soon after issuing from
the pupa stage, there is room for a number of generations

FAMILY MUSCIDM

281

during even a nortliern summer, probably from six to eight
being common.

For the destruction of the larvse, which is probably the
most effective way of preventing damage, two principles
have been established. The first involves the killing of the
maggots by introduction of some destructive agent; the
other, the prevention of their maturing by the rapid drying

Fjg. 225. — ^Horn fly {Hemalobia serrala): a, egg; b, larva; c, puparium;
d, adult in biting position. All enlarged. (From Riley and Howard.)

of the mass of dung which supplies their food. The use of
lime, as originally suggested in Insect Life, is a very effective
plan, and where not prohibited by expense, should be generally
adopted. Prof. Smith's suggestion to spread out the drop-
pings of manure so that they may dry rapidly is applicable
during dry weather and in some localities is accomplished by
drawing brush across the fields, a method which must

282

ORDER DIPT ERA

necessarily fail to be complete in its operation, but much less
expensive than the use of a shovel by hand.

The Stable Fly {Stomoxys calcitrans, Linn.). — The stable
fly is a well-known species which is widely distributed and a
familiar pest in many countries. Its bite is severe and it
causes a great amount of annoyance to cattle, horses and
other domestic animals, and is frequently very troublesome
to people working in places where it abounds. It is not
confined to stables or to the quarters of domestic animals,
but occurs frequently in shady places, gro\es and in dwell-

FiG. 226. — Stomoxys calcitrans: adult, larva, puparium, and details — all
enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.)

ings, especially in cloudy weather, and puts the occupants
to great inconvenience. Its bite is not poisonous, and aside
from the pain given and the possibility of it disseminating
disease, it is less injurious than some other members of the
group. When abundant, however, this annoyance may be
very great, and they all deserve attention. Indeed, it is
especially charged against this species that they have been
the means of transmitting glanders from diseased to healthy
horses, and anthrax among cattle, a charge which appears
very reasonable from the fact that it inflicts a deep bite and

FAMILY M use I DM

283

does not gorge itself at a single animal, but nia\' fly from
one to another in securing a meal.

In late years it has come into especial prominence as a
a carrier of disease. It was at one time thought to be the
carrier of infantile paralysis but this relation has not been
substantiated.

Fig. 227. — Muscina stabulans: a, larva; b, head below; c, head, side
view; d, thoracic spiiacle; e, stigmatic plate; /, female; g, head of female;
h, mouth parts; i, antenna. All enlarged, d, c, h, i, greatly enlarged. (Bur.
Ent., U. S. Dept. Ag.)

Tsetse Flies. — The tsetse flies have been notorious for a
long period as extremely serious pests in parts of Africa
and were described by early explorers because of heavy loss
to domestic and wild animals. In recent years these have
been connected with the transmission of certain kinds of
diseases, and are now looked upon as having a most impor-
tant bearing from the medical standpoint.

The species longest known, Glossina morsitans, has been
especially connected with loss among cattle, and horses.
Glossina palpalis which has been determined as the cause

284

ORDER DIPTERA

Fig. 228. — Glossina palpalis (X 3f), the carrier of the trypanosome of
sleeping sickness. (Bruce.)

Fig. 229. — Phormia lerraenovcE — enlarged. (Howard, Div. Ent., U. S.
Dept. Ag.)

FAMILY MUSCIDM 285

of sleeping sickness in man has received perhaps the greater
attention in recent years.

It can easily be seen that the introduction of either of
these species into this country or even into South America,
with the opportunity for further distribution would be a
most serious menace, as there would be every possibility of
the introduction of the diseases which are associated with it.
These are perhaps examples of insects which deserve most
careful attention from the stand-point of possible exclusion,
and every effort made to learn their habits in detail and to

Fig. 230. — Lucilia cccsar — enlarged. (Howard, Div. Ent., U. S. Dept. Ag.)

avoid such means of transportation as might possibly serve
to transfer them to this country. ■ It is reported that such
an introduction has occurred in Australia.

Blue-bottle Fly {Lucilia ccesar).- — The blue-bottle fly is
another species which is very abundant and almost uni-
versally distributed. Its attacks are made upon any avail-
able fleshy material such as carcasses of dead animals, fish,
and so on. The female deposits eggs on living animals that
have bruises or wounds or attractive points for deposition.
Sheep are especially subject to attacks of this sort. The
maggots of the flies do not limit themselves to the external

280

ORDER DIPTERA

parts but burrow into the flesh and may perhaps cause very
serious injury.

The meat fly or blow fly is another species that falls in
the same group with regard to its habits, and against which
it is important to protect domestic animals.

Flesh Flies iSarrophagida'). — Flesh flies are (piite familiar
objects around houses, especially if there is any exposiu-e of

Fig. 231. — The green-bottle fly: a, egg masses in cow dung; h, hatched
egg; c, a portion of the egg surface seen under the microscope; d, unhatched
egg; e, larva. All enlarged except a. (From Ann. Rept., U. S. Dept. Ag.,
1890.)

fresh meats to attract them. The eggs are laid on meat by
preference and hatching occurs within a very short time, in
fact in some species it is stated that larvse are extruded from
the adult. Aside from their deposition upon meats, how-
ever, there is often a deposition upon fresh wounds or abra-
sions so that the larvae may make a serious attack upon
domestic animals or even human beings, if there is an opi)or-
tunity for the attack. As a protection against this kind of

FLESH FLIES

287

injury it is important that all bruises or scratches should
be treated promptly so that domestic animals will not serve
as an attraction for the species.

7 ■\-^'7"\

Fig. 232. — Homalomyia brevii: female at left; male at centie, with
antenna enlarged; larva at right. All enlarged. (Aftei Howard, Bur. Ent.,
U. S. Dept. Ag.)

Fig. 2.33. — Apple maggot {Rhagoletis pomonclla) : a, adult; b, larva or
maggot; c, funnel of cephalic spiracle; d, puparium; e, portion of apple
showing injury by maggots; a, b, and d, enlarged; c, still more enlarged;
e, reduced. (After Qviaintance.)

In the genus Drosophila are a number of species, the
"pomace flies" which feed principally upon decaying fruits.

288 ORDER DIPTERA

They are perhaps of sHght economic importance as they do not
attack growing plants, but on accoimt of the great ease with
which they may be bred in captivity they have been the
basis of some most important investigations concerning the
transmission of hereditary characters.

Another species is one that occurs as a pest in apples and
is known as the apple maggot (Rhagoletis pomo7iella), which
differs in its method of work from the codling moth larvae
in that the larvse work near the skin and make tunnels
through the apple. It punctures the skin and deposits eggs
inside. This goes on during the summer and the larvae
mature in autumn with the maturing of the fruit. They
hibernate as pupae. This species occurs now and then in
Ohio, but is not so universally common as the apple worm.
It is more distinctly a northern species, sometimes a serious
pest in New England and parts of the States and Canada
bordering on the Great Lakes.

Family Hippoboscidse. — The family Ilijjpohoscidce includes
sheep ticks, and forest flies. They have the wing structure
of the Diptera, suctorial mouth parts, but a very remarkable
method of reproduction. Instead of extruding eggs, they are
retained in the oviducts and developed through the larval
stage, being nourished by nutritive fluids. They are not
extruded until they are ready to pass into the pupa stage.
They take no nutriment as pupae after leaving the oviducts.
There is no food taken until as adults. There is an adapta-
tion for the parasitic habit. This is a different sort of adapta-
tion than is found in any other group of Diptera except the
succeeding group. They are different from any other group
of animals.

Sheep Tick (Mcloijluigiis uviniis, Linn.). — The sheep tick is
a common pest of sheep. It differs from the most of the
other members of the family in never possessing wings. The
head is small and sunken into the prothorax. The middle
portion of the prothorax is rather slender, contrasting with
the development of this region in the winged forms.

It is of a reddish or gray-brown color, about one-fourth of
an inch long, and easily detected when present in any num-

ORDER SIPHON APTERA 289

ber on sheep. They never migrate from tJie original host
except it be to attach to another animal of the same species,
and probably the principal movement is that which occurs
after sheep are sheared, when the ticks tend to migrate to
lambs. On the sheep, if abundant, they may cause con-
siderable (himage, indicated by lack of growth or poor
condition, and when massing upon lambs they may cause
great damage, resulting in the death of the victims if not
promptly relieved.

They are distributed over the world generally where
sheep are kept, and are too well known by sheep breeders
to make it necessary to emphasize the injury they may
cause. All breeds of sheep seem alike subject to attack,
but I know of no record of their occurrence upon other
animals.

While the ticks may be greatly lessened in number by the
vigorous use of pyrethrum — a most available remedy during
winter — the most practical plan to adopt, and one which if
thoroughly followed will make all others unnecessary, is to
dip the sheep each year after shearing.

A flock once freed from the pests will not be again infested
except by the introduction of infested animals: hence care
should be taken in making additions to the flock to free the
newcomers from parasites. It is also well to keep the sheep
for a few days after dipping in a different inclosure from
that occupied before, to avoid possible infestation from any
stragglers that may have been caught on wool upon posts
or brush, and if the wool is charged with them when clipped,
it should be stored where the ticks could not easily return to
the sheep. The ticks cannot travel any distance inde-
pendently, and will soon die when removed from the sheep,
and proper care here will insure success.

Order SIPHONAPTERA.

Another order is the Siphonaptera. The fleas are wingless
or have the wings so aborted that they are practically wing-
less. Vestiges of wings may occur but are useless as organs
19

290

ORDER SIPHON A PTERA

of locomotion. The adults have suctorial mouth parts and
puncture various kinds of animals, suckinji; the blood for a
food supply. The larvte are slender and live in refuse and
rubbish, litter of do<i kennels, etc., and when mature change
to a very distinct pupa stage and then to adult flea. The
]nipa stage is like the adult in shape but the legs, etc., are
encased in the rigid pupa case. The hindlegs are specially

Fig. 234. — Cat and dog flea (Cttnuttphalus ciniis): a, egg; b, larva in
cocoon; c, pupa; d, adult; e, mouth-parts of same from side; /, antenna;
0, labium from below; b, c, d, much enlarged; a, e, f, g, more enlarged.
(After Howard.)

developed and their mode of progression is by leaping.
They occur on different kinds of animals, as the dog and cat,
and there are species that occur in houses, on squirrels,
rats, mice, and various mammals. It is mainly on the
smaller species of mammals, and one species occurs on birds.
One species attacks poultry. It buries itself in the skin
something like a jigger, though not so extreme in the extent
to which it will burrow.

CHAPTER X.
BEES AND WASPS.

Order HYMENOPTERA.

The Hymenoptera are in some respects the culmination
of the group of insects. They are speciaHzed in several ways
but the species are all characterized by ha^'ing the mouth
parts developed into both biting and sucking structures.
In some respects they seem more specialized than all other
orders and in some respects they seem less specialized than
the Diptera and Lepidoptera. As a matter of fact in the
evolution of the groups of insects there are several orders
that must be looked upon as having evolved along divergent
lines at the same time and none can be said to really outrank
the others. The Coleoptera, Diptera, Lepidoptera, and
Hymenoptera, all have a high degree of specialization. It
is better not to try to consider them as in the line of a series
of steps running up, but as parallel or divergent branches
from a general trunk, all of them extending to extreme
distances from the primiti^'e stock.

The Hymenoptera have four wings, and these are pro\'ided
with rather few veins and pretty highly specialized in the
venation, and in a few groups the veins are practically
reduced to nothing. The mandibles are present for the most
part in the adult forms l)ut are almost lost in some forms that
are fed by the adults in communal forms. They are both
mandibulate and haustellate. The larva? are usually footless,
fleshy, grub-like animals which depend on their food being
sui)plied for them in one way or another and are incapable
of moving about and securing their own food supply. This
represents a high degree of specialization and reaches its

(291)

292 BEES AND WASPS

culmination in the community habit of ants and bees. In
no other si'oup except the white ants is there such develop-
ment of the community habit.

The pupa stage is generally included in the nest or cells
formed for the larval stage, and the forms are seen to be
quite highly speciahzed when the cocoon is cut open. The
larvffi moult but the moults are not so conspicuous as in
exposed forms. The group exliibits quite a variety of
habit, some leaf-eating forms, some wood-boring forms,
some that develop in galls, many that are parasitic inter-
nally on other insects, and many store food in their nests,
such as spiders, caterpillars, etc. These are sometimes
stored in the ground, sometimes in mud cells, sometimes in
channels in the wood, sometimes in paper cells.

There are two large divisions, the Phytophaga, leaf-eating
or plant-feeding free caterpillar-like forms, and the Aculeata
wliich represent the other forms of the group, the larvje of
which are dependent on a food supply provided by the adult.
The adults of this group have a sting.

The group T enihrediindoe is a large family of leaf-eating
and gall-making insects and the typical ones being the
willow saw fly and the gall-making willow forms.

The willow saw fly {Cimhcx americana) is one of the largest
species that we have. The adult is steel blue, the wings
smoky. It is quite conspicuous and lays its eggs on the
leaves of the willow along the midrib and principal veins of
the leaf. The larvse hatch in a few days and grow during
the midsummer and are noticed as large yellow^ caterpillar-
like forms clinging to the twigs and leaves of willow par-
ticularly or sometimes also to elms and a few other kinds of
of trees. Some of the larvae have a prominent black dorsal
line. They coil themselves quite a little especially when
resting. While feeding the body is stretched out and they
cling by means of the prolegs of the abdomen as well as by
the thoracic legs. Prolegs are similar to those of the cater-
pillar. There are certain similarities with some of the very
generalized Lepidoptera and the prolegs might possibly be
taken to indicate some affinity. However, it is probably

ORDER HYMENOPTERA 293

better to look upon it as an independent development of a
similar structure based on similar habit. The number of
prolegs varies from twelve to sixteen. There are twenty-two
legs altogether. The saw fly larvae become fully grown by
the latter part of the summer and secrete themselves near
the surface of the ground, generally among dead leaves and
rubbish. They spin a quite strong silken cocoon w^ith a
papery texture, somewhat more dense than is common for the
caterpillars of the silk-making moths. In this cocoon they
remain as larvae for quite a period. They finally pupate and
the adults issue in the spring and deposit eggs so as to
produce the summer generation of willow worms. They
become of economic importance where the shade trees they
feed upon are of importance — willow trees, elm, etc. They
are parasitized and the cocoons are eaten by mice and so
kept down generally to a moderate number and are not
usually very destructive.

The pear slug (Eriocampoides limacina) occurs quite
commonly in orchards and attacks not only the pear, from
which it dervies its name, but also apple and other orchard
trees. The larva has a strict resemblance to the mollusks
called slugs, as the body is covered with a dense slimy secre-
tion which hides the segmentation and external features of
the body. They feed upon the surface of the leaves, just
leaving ribs and veins. The trees attacked often have the
appearance of being scorched by fire.

They are best treated by the application of arsenical solu-
tions, applied as soon as their work appears.

The American rose slug {Endelomyia rosce) is frequently
troublesome in its attacks on the leaves of rose bushes which
are stripped or skeletonized so that the bushes are rendered
quite unsightly.

Arsenical solutions can be used, or if these are not desired,
hellebore may be used for their control. Other species
affect gooseberry, strawberry and other such crops. Many
instances being of considerable importance.

The Uroceridoe are wood- or stem-boring species and
more specialized than most of the preceding family.

294

BEES AND WASPS

One form is particularly interesting, Tremex columha, or
horn tail or pigeon tremex. It has a rather peculiar shape
both in the larval and adult stages. The adult is an inch
or more in length and with a prominent ovipositor which
extends back about one-half inch from the back of the
abdomen; both larva? and insects are cylindrical, the result
of the boring habit. These adults appear in summer and
deposit eggs on the bark of different kinds of forest trees —
sycamore, maple, and others. The larvi^ burrow in, form-

FiG. 236. — Pear slug: «, adult saw fly, female; b, larva with slime
removed; c, same in normal state; d, leaves with larvoe, natural size;
«, 6, c, much enlarged. (From Marlatt, Div. Ent., U. S. Dept. Ag.)

ing tunnels through- the heart wood pretty well down into
the tree. Sometimes the trees are extensively perforated.
Boring continues in through the tissue of the wood till they
get their maturity and then they burrow out through the
bark. Pupse are formed in the burrow near to the surface
of the tree and the adult works its way out from the cocoon
after the pupa is split open. Occasionally the adults will
be found with the ovipositor fast in the bark of the tree
or in the wood. They burrow in to deposit eggs and seem

ORDER HYMENOPTERA 295

unable to withdraw the ovipositor. Presumably they
deposit a single egg in each perforation. There are two
common parasitic species, Thalessa atraia and lunator,
which are the natural check upon the multiplication of this
form and which ordinarily keep its numbers down to narrow
limits. Without this check the species would probably mul-
tiply to a great extent. The parasites are representatives
of another family, Ichneuimmidcp. They are rather slender-
bodied and with extremely long ovipositors. In Thalessa
atrata they are four or five inches long. These are driven into
the burrows of the tremex and the eggs are deposited in the
burrow and presumably at some point close to the tremex
larva. The larva of the Thalessa is said to attack the tremex
larva externally and not to be internally parasitic — a little
variation from the general habit of parasitism for the family.

Cynipidse. — The Cympidoe are in one sense a vegetable-
feeding group, though some are hosts or guests of gall-makers.
The primary feature is that they make galls and the larvse
develop within these galls. Galls are not a normal plant
product, nor a profluct of the insect alone, but a combina-
tion product of the insect and the plant. A stimulus given
to the plant cells results in a definite specific form of growth
which is just as specific as the form of the leaf or the fruit
of the plant on which it is formed. Species can be deter-
mined accurately from the form and structure of the gall.
The most familiar of these galls are the oak apples. These
are rich in tannic acid which gives the gall a decided flavor.
A globular structure is built out by a great growth of plant
cells. The gall grows and develops more rapidly than the
larva. The larva gets its growth by eating the cells which
are close to it and all the rest of the structure is apparently
developed purely as a protective device for the larva.
The greatest number of species occur on oaks, some on
roses, etc. There are dozens of dift'erent kinds on oaks and
many different species on a single species of oak and some
restricted to one certain species of oak alone.

Parasitica includes several families: Ichnemnonidw, a large
group iBraconidcEiChah-id idee, a large group ;and Proctotriqndw.

296 BEES AND WASPS

All of these are distinctly parasitic in habit. Braconidce
and Ichneumunidoe are the more generalized kinds of para-
sites and parasitize such forms as the caterpillars of the
Lepidoptera in immense numbers. They constitute a very
important check upon a number of very important species.
It is hard to do much in the way of encouragement of them,
though they may be transported from one country to
another. One subfamily is pretty commonly parasitic on
plant lice.

ChalcididcB form a specialized group with much reduced
venation for the wings and the Prodotrupidce are minute
and largely egg parasites.

Family Ichneumonidse. — The Ichneumon flies include
many of the larger species of parasitic Hymenoptera and a
number of species which have important economic bearing
on the abundance of destructive species. Good examples are
to be noted in the species of Thalessa which parasitizes the
pigeon tremex and in species of Ophioii which attack a num-
ber of different kinds of caterpillars. The species of Pimpla
are also conspicuous members of the group and their attacks
are made especially upon injurious species of moths, so that
they are to be counted distinctly serviceable.

Pimpla conquisitor is one of the parasites of the tent cater-
pillar and it is possibly due to this species that the tent
caterpillar is less destructive than it otherwise might be. In
this species the parasite lays its eggs in the cocoon of the
host and its larva develops within the pupa, so that it
serves to prevent the development of the adult and the
deposition of the eggs which would follow.

Family Braconidae. — The family BraconidcF is quite similar
to the preceding but the species are on the average smaller
and many of the species parasitize the minuter kinds of
insects such as plant lice. A quite common species is Apan-
teles (jlomeratus which is a parasite of the common cabbage
worm and which no doubt serves as a quite important factor
in assisting to keep this pest in check.

Perhaps one of the most important species is the little
Lysiphlehus tritici which is a very abundant parasite of

ORDER. HYMENOPTERA

297

Fig. 236. — Pimpla conquisitor, an important parasite of the tent cater-
pillar: a, larva, enlarged; 6, head of same, still more enlarged; c, pupa; d,
adult female, enlarged; e, f, end of abdomen of adult male, still more
enlarged. (From Fourth Report, U. S. Ent. Con.)

Fig. 237. — Apanlcles glomeratus: a, adult fly; 6, cocoon; c, flies escaping
from cocoons; a, 6, highly magnified; c,. natural size. (After Chittenden,
Div. Ent., U. S. Dept. Ag.)

298

BEES AND WASPS

aphids. It is a minute species and its larva maintains its
entire growth within the body of an aphid, the entire con-

FiG. 238. — Parasitized cabbage worm I^Pontia rapce), showing coroon
mass of Apantdes glotturalus VjcIow. (From Chittenden, Div. Ent., U. S.
Dept. Ag.)

Fig. 239. — Lysiphlebus tritici, principal parasite of the spring grain aphis:
adult female and antenna of male, greatly enlarged. (Webster, Div. Ent.,
U. S Dept. Ag.)

ORDER HYMENOPTERA

299

tents of which are not equal to a drop of water. However,
the parasite may feed upon the aphid during some httle
time and is supplied with food from the efforts of the aphid

Fig. 240. — Wingless female of "green V)Ug" containing larva of the
parasite Lysiphlebus tritici. Much enlarged. (W'ebster, Div. Ent., U. S.
Dept. Ag.)

sucking nutriment from the plant. This species is consid-
ered one of the principal agents in control of the spring grain
aphis or the "green bug" which during recent years has

Fig. 241. — Lysiphlebus depositing its eggs in the l^ody of a grain aphis.
Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.)

caused extensive injury to the wheat crop in the south-
western part of the country. Its attack seems to be dis-
tributed, however, over a number of si)ecies and it is therefore

300

BEES AND WASPS

able to maintain itself even in the absence of any one species
of plant lonse.

Fig. 242. — Pteromalus puparum: female at left; male at right — highly
magnified. (Chittenden, Div. Ent., U. S. Dept. Ag.)

Fig. 243. — Chalcis ovata, a parasite of the alfalfa caterpillar: a, pupa;
b, parasitized pupa of tussock moth (Hemerocampa leucostigma) : c, adult;
d, same in profile; e, pupal exuvium. Enlarged. (From Howard.)

Family Chalcididae. — The family Chalcididop, one of the
groups which includes extremely minute insect forms which
parasitize insects, such as the plant lice, scale insects, and

ORDER IIYMENOPTERA 301

many other forms. They have broad liearls, rather thick
jaws and are quite generally of brilliant metallic colors. A
distinctive character is found in the reduction in the veins
in the wings so that only the costal vein borders the front
margin of the wing and is so developed as to be rigid. In
larger insects a great number of these parasites may develop
in a single individual. In the smaller species usually a
single parasite is found in the host. They are especially

Fig. 244. — Isosomn triiici: adult of the joint worm — much enlarged.
Howard, Div. Ent., U. S. Dept. Ag.)

effective in the destruction of scale insects, and some of the
species are parasitic in the eggs of other insects. In some
cases they become secondary or tertiary parasites in which
case their value is changed.

Pteromalus puparum, one of the parasites of the cabbage
worm, is apparently distributed well over the area occupied
by this species and its attacks upon the host form serve as
one of the quite constant checks upon the abundance of that
species. The parasitized pupix? usually show a different

:3()2

BEES AND WASPS

color, and if observed tliese may be allowed to remain in
the fields with the expectation of the parasite serving a
good purpose for a later generation. If possible it is well
to assist them somewhat by putting the pupse under screens
which will permit the escape of the parasites, without
allowing the escape of butterflies which might issue from
healthy pupte.

While most of these species are parasitic, there are a few
which are plant feeders, and notable among these is the

-■i

Fig. 245. — Bits of hardened straw remaining with the grain after
thrashing. (After Webster, Div. Ent.. U. S. Dept. Ag.)

wheat joint worm {Isosonia tritici), which is the cause of a
great deal of damage to wheat in many parts of the country.
The presence of the joint worm is evidenced by the forma-
tion of woody places in the stem, within which the worm
is found and the effect of its injury is to cause the stems to
become weakened so that freciuently the grain will be broken
down, especially if there are severe winds. The insects pupate
within the stems and remain in the pupal stage all winter.
This accounts for their frequently being fountl in chaff" or

ORDER HYMENOPTERA

303

straw. Sometimes the hard pieces of straw are carried over
in tile threshing and mixed with the grain. It is evident

Fig. 21(). — Iso^oma trilid: female ovipositing. (Photo by Ohio Exi). Sta.)

that burning of the stulible in the fall or early spring will
destroy the pupa in the fields and it is considered that the
use of straw and cliaif in the bedding of stock or as fodder

304 BEES AND WASPS

is an excellent plan to reduce the infestation. Of course
burning chaff or straw would accomplish the purpose, but

Fig. 247. — Isosoma trilici: adult male. (Photo by Ohio Exp. Sta.)

Fig. 248. — Isosoina tritici: larvae. (Photo by Ohio Exp. Sta.)

this is not deemed necessary if the straw passes through the
barnyard, as most of the pupa? are killed by this treatment.

ORDER HYMENOPTERA 305

The egg parasites (Prodotnqndoe) are extremely small, most
of the species being parasitic in the eggs of insects. Eggs of
web worms are parasitized and the whole development of
the Proctotrujnd is contained within the egg. One species
is described as one-nintieth of an inch in length, another one
one-hundred-and-fiftieth of an inch and the body very slender.
These serve a most important function in the destruction of
other insects, those that would otherwise hatch from the
eggs. When the parasites feed on the caterpillars the damage
is only partly checked, but when the parasite feeds on the
eggs the damage is all prevented. One of the important lines
of economic entomology is to study such forms and their
life histories with regard to other species, as primary para-
sites, secondary parasites, tertiary parasites, etc., since
their value depends on whether they directly control a pest
or whether as a secondary parasite they reduce the niunbers
of a primary parasite which is useful.

Ants (Formicina) are one of the most interesting groups
of insects. They are sometimes given the rank of a superior
family, but the principal family is that called Formicidce.
The name is associated with the secretion of formic acid.
The name of the group probably gave the name to the
chemical. The secretion is one of the characteristics of the
Hymenoptera. Ants present striking habits of family life;
the formation of different classes among the individuals
of a colony. This separation into classes is paralleled in
other groups, as the bee family and among wasps, and
expecially the termites. The result of community life is
that it presents certain relations in the community in the
way of division of labor. The primary forms are males
and females, and then a class which are not sexual but are
derived from a modification or suppression of the reproduc-
tive factor in one of the sexes. Occurring with this is the
reduction or complete absence of wings. These constitute
the so-called workers or soldiers of a colony. They have no
wings whatever. This feature reaches far back into the
ancestry of the group, or else shows parallel evolution.
Sexual individuals have wings primarily but in the case of
20

306 BEES AND WASPS

the queens the wings are broken off or dropped oflf after the
flight associated with mating. Then the females are unable
to travel and remain fixed in a certain colony and furnish
oft'spring for the colony. A group of ants is called a formi-
cary. It may vary in number of individuals from a few
hundreds to thousands. A single queen ant may survive
for a great number of years and the same colony may go on
for many years. The usual course of the life-cycle is for
winged females to issue from some colony and make their
flight that is connected with mating, and then to burrow
into the ground or select a suitable nest to place the eggs
and begin the formation of a new colony. The fertilized
queen is capable of producing workers and in some cases the
cjueen alone will start a colony. In some forms perhaps the
help of other ants is needed. With the starting of the
colony and the deposition of eggs a colony becomes more
populous. Difterentiation has not gone quite so far in ant
colonies as in some others. The workers take care of the
eggs and the young and shift the young about, and if the
nest is disturbed they carry the pupae to a place of safety.
The pupse are, of course, helpless. The workers and soldiers
die off pretty rapidly. They survive through the working
period and when they die are replaced by other workers.
The colony retains its individuality year after year. The
life of the colony is probably at least as long as the life of
the queen and probably continues longer than that. Other-
wise the colony w^ould have to terminate soon after the
death of the queen. The multiplication of colonies is pro-
^■ided for by the issuing of new queens from the colonies
and the ability of the ant to sur^'ive depends as much on
its ability to form new colonies as on new individuals.
There is just as much reproduction of colonies as of indi-
viduals. The cycle is probably for annual periods in each
season and the females are probably produced annually.
The food of the ants is primarily plant food. They collect
nectar and various substances of vegetable origin, and the
workers are responsible for the collecting and storing and
using of the food supply. Indirectly they get such supplies

ORDER HYMENOPTERA 307

from the aphids. They store up grain in some instances,
and use this grain to some extent at least as a food
supply.

One of the species — the honey ants — collect honey and
store it in the stomachs of certain individuals of the colony.
The bodies of these individuals become very much distended
and the abdomen becomes large and spherical and these
keep the food for a part of the year. This ant occurs in the
plateau regions of Colorado, particularly in the Garden of
the Gods. The volume by McCook on these ants is an
especially interesting account of animal adaptation. Also
Lubbock's book on A7its, Bees and Wasps gives many
interesting experiments, but his observations indicated that
while there is an adaptation to complex conditions they are
not comparable to the activities of human beings.

There are many species — little red ants, those occurring
in gardens, and walks, the house ants, and the large car-
penter ants, which form nests in hollow logs. The queen is
quite a large insect and usually with wings entirely wanting.
Large red ants and large black ants construct hills for their
nests, sometimes three to six or eight inches high, and
perhaps twelve to eighteen inches across the top. This red
ant is a slave-making species, going out on forays and
capturing black ants which they force to carry on the labor
of the colony. Some species are said to have carried the
slave-making habit to such an extreme that they are unable
to get along without the slaves and even require slaves to
go out and capture new slaves.

Field Ants.— One of the important species is the little
field ant which is associated with the corn-root louse and
which has been named in connection with the discussion of
the aphid. This species is very widely distributed through-
out the United States and wherever corn is grown and the
corn-root louse is present it constitutes an important factor
in the abundance and destructiveness of the root louse.

The Argentine ant {Iridomyrmex Innnilis Mayr) is one of
the recently introduced pests and one which is liable to
become distributed to cover the Southern States and possibly

308 BEES AND WASPS

to occupy at least the cotton-growing region if not a greater
extent of the country.

The species is thought to have been intro(hiced from
Argentina and was first noticed in New Orleans where it
was reported as occurring in fair numbers in 1891. It is
now known throughout most of Louisiana and in eastern
Texas, and also occurs in California. Within the range of
its distribution it has become a very serious pest and its
further distribution will naturally be a matter of serious
consequence to other localities. Without assistance the
ant migrates slowly but with the opportunities afforded
by commerce its dispersal may be quite rapid.

As with the other ants there are males, females, and
neuters; the males and females being winged, the neuters
wingless but the females lose their wings after the mating
flight.

The size of the colonies varies from a few individuals to
many thousands and a number of queens may be present
in each colony. The nests are built in various places under-
ground, seldom occurring at any great depth.

This species is a most difficult one to control and experi-
ments with poisonous materials, repellants, etc., have met
with only partial success.

Wasps iSpherina). — In this group we have a considerable
number of solitary forms of those which preserve the primi-
tive conditions of males and females without workers or
with large broods raised at one time in one nest. Mud,
paper, pith, etc., are used as building materials. The sand
wasp {Bembecince) burrows into the sand for its nest. They
stock these nests with insects of diff'erent kinds such as May
flies. The larvse develop by feeding upon the bodies of these
stored insects. It is strange that they can keep a burrow
complete enough so that they can pass in and out a number
of times. They are very common here and are protected
to some extent by the coloration of the body. Their bur-
rows are constructed along through the summer and the
larvae develop during the summer and presumably all reach
the pupa stage before winter and live over as pupse, issuing

ORDER HYMENOPTERA

309

the following season. The adults will be found flying around
all through the midsummer months. Perhaps they are a

Fig. 249. — The Argentine ant, adult forms: a, adult male; al, head of
male; a2, petiole of male; h, worker; bl, head of worker; h2, petiole of
worker; c, fertile queen; cl, head of queen; c2, petiole of queen. All
greatly enlarged. (After Newell.)

310 BEES AND WASPS

little more abundant in the later part of July. They belong
to the Bcmhecidce. One of the large members of the family
is called the "cicada killer" Syhecius speciosus.

Social wasps (Vespidce) make large nests and large colon-
ies and show some degree of differentiation into classes or
castes of individuals in that there may be smaller indi-
viduals at the end of the season which live through the
winter.

The Hornet {Vespa maculata) builds up a large paper nest
which is made up of a series of combs with the aperture at
the lower part. This becomes very populous during the
latter part of summer. The survivors are adults that secrete
themselves under leaves and rubbish and start a fresh
colony the succeeding year. They do not live in the large
nest through the winter. This common species is social.

The yellow jacket (Vespa germanica) is also a social
species, its nests are found in hollow trees.

It is interesting to compare the materials used by these
species. They use wood or paper which is a pulp worked up
from the wood fiber and is to be compared with manufactured
paper in the tissue of which it is made and in the manner of
manipulation.

In the bees, Apidce, there is an elongation of the beak for
getting the nectar from the flowers and the more specialized
forms secrete wax for the formation of the cells. This is
worked up into a gum or built into cells for the rearing of
the larvae. There is a gradual culmination in the develop-
ment of community life in this family from the wild bees that
are practically solitary up to the bumble bee and honey bee.
The honey bee is probably the best-known because kept
under domestication. A bee colony consists of a queen, which
is a constant factor in the colony-^a queenless colony can-
not survive any length of time — and drones or males which
occur during the summer. These are the normal-sexed indi-
viduals. Then we have the workers or neuter forms which
are undeveloped females and these carry on all of the com-
plex work of the colony, providing food, caring for the larvae
and for the rearing of new queens.

ORDER HYMENOPTERA 311

The cycle as applied to the queen would involve three to
five years. They live that long and deposit millions of eggs
during that time. The drones live but a short period. The
workers live a few weeks or months through the summer
and in the more inactive parts of the year. The queens from
the egg stage to the adult stage occupy about sixteen days,
the workers twenty-one days, the drones twenty-four days.
There is a distinct difference in the eggs that produce workers
and drones. The worker eggs are fertilizecl and the drone
eggs are unfertilized. This is apparently controlled by
the queen and dependent upon the kind of cells in which
the eggs are laid. The exact method of control by the
queen is not fully understood. The size of the cells may have
some effect by the pressure on the abdomen. The accelera-
tion of the queen may be because the workers feed them with
a richer sort of food. They develop more rapidly and the
reproductive organs are fully developed. There is colony
reproduction as well as individual reproduction, that is, an
increase in the number of colonies. They die off from old
age, loss of queen, cold weather, etc., and if there were no
process for increasing the number of the colonies they
would be exterminated. This is provided for by swarming.
The queen and a large number of workers issue from the
colony and form a new colony. The old colony is provided
for by other young queens in the cells or else fertilized.
There is a loss of honey but no break in the life of the colony.
Bee-keeping is an important industry and there are many
books dealing with the subject. Among those of special
value are the following:

Cheshire, Honey Bee. Root, Bee-keeping. Langstroth, Hive and Honey
Bee. Snodgrass, Anatomy of the Bee. Benton, The Honey Bee. Cook,
Manual of Bee-keeping. Conistock, How to Keep Bees. Phillips, Bee-
keeping. Pellett, Productive Bee-keeping.

CHAPTER XI.

PRINCIPLES OF ECONOMIC ENTOMOLOGY.

While it cannot be assinned that we have at present a
complete knowledge of those underlying principles which
are to be recognized in the prevention or control of insect
ravages, enough has been done to make an attempt at a
brief statement of such principles in order. Many of these
principles have been stated in greater or less detail in the
writings of different entomologists but no comprehensive
statement has been attempted — especially since the marked
advances of the past quarter-century. Applied entomology
today is a totally different structure than that which
existed twenty or even ten years ago. In many respects it
is getting nearer to the fundamental laws of biology, and
there is a more general appreciation that its successful appli-
cation involves thorough acquaintance with biological prin-
ciples. In the broadest sense economic entomology involves
a recognition of the relation existing between insects and
other organisms, but finally, the relation they bear to the
human species.

RELATION OF INSECTS TO OTHER ORGANISMS.

Considering the great multiplicity of insect forms, their
world-wide distribution in almost every condition open to
the su])port of life, it is not strange they occupy a most
important relation to other organisms. This relation may be
serviceable or inimical, directly or indirectly from the
stand-point of any particular organism, and may indeed
differ totally at different times or under different conditions.
From the stand-point of any particular species it is detri-
(312)

ECONOMIC ENTOMOLOGY 313

mental if the insect feeds upon the plant or animal or inter-
feres with its successful existence. It is beneficial, if it
contributes to its success by warding off other dangers or
assisting pollination or contributing in any way to its better
growth and development.

ECONOMIC ENTOMOLOGY.

Economic entomology is based upon the relation of
insects to mankind and all species that interfere with his
welfare are considered injurious, and those that may serve
him in any way are considered beneficial. The relation,
however, may become very complex. An insect that feeds
upon a cultivated crop, or destroys the products of a crop,
or injures a domestic animal, or worries man himself, or
menaces his health by inoculating him with disease, is
injurious from the human stand-point. While if it produces
a valuable material such as silk or honey, wax, dyes, etc.,
or serves to destroy injurious species as predaceous and
parasitic forms, or feeds upon noxious plants, weeds, or dis-
poses of noxious substances, as the scavengers, it is directly
useful, and we term it beneficial. Many cases are very clearly
in one class or the other; many have little apparent impor-
tance one way or the other, and in many cases the relation
may change with circumstances. For example, a parasitic
insect preying on an injurious species is useful to us, but if
it destroys a useful insect it becomes injurious. A parasite
on a parasite, that is, a secondary parasite is detrimental if
the primary parasite attacks an injurious insect, and a
parasite upon this secondary parasite, that is, a tertiary
parasite would be useful, since its effect would be to check
the secondary and favor the ])rimary parasite. Still further,
a quaternary parasite, and this is I believe as far as this
relation is known, would be injurious. The reverse in each
case would be true if the original host were useful.

We should not forget that these three terms refer strictly
to mankind, for in the broader biological sense each kind of

314 PRINCIPLES OF ECONOMIC ENTOMOLOGY

animal is doing its best to perpetuate itself and multiply
its kind, and every interference is from its stand-point
injurious.

FOOD HABITS.

It is very evident that one of the first and most important
relations concerning an insect is to be found in its food
habits.

Insects, like other animals, may be considered primarily
herbivorous. That is, the most general plan of nutrition
for them would be to feed u])on fresh, growing leaves of
plants, with feeding ujjon fruits, seeds, bark, wood, roots,
decaying wood as adaptations, while the assumption of car-
nivorous habits either as predaceous or parasitic species, or
to go further, sucking blood of higher animals may be
considered adaptations in another direction.

It is on this broad, general basis that we may consider
herbivorous insects in the main injurious, and carnivorous
insects, especially if predaceous and parasitic on other insects,
as beneficial.

In this connection we may refer to the principle which
has been termed ''unity of habit" and treated by Dr. B. D.
Walsh. This is in effect that in any given group we may
expect to find similar habits among all the species, and if for
any species the habits are unknown, the^^ may be expected
to follow those of the known species. To this law there may
be striking exception, however, and along certain lines
peculiarities should be considered the rule and not the
exception. To find the most certain action of the law we
may, I think, say that in all particularly specialized groups
"unity of habit" is practically general. In less specialized
groups variation is more frequent. For example, in the bark
beetles, ScolytidcE, we would be astonished to find a leaf-
eating larva, or in Aradidce a species that does not live under
bark is exceptional. In Lepidoptera, the larval diet is gener-
ally herbivorous and the two or three carnivorous species
notably the exception. We safely assume that all plant
lice are plant feeders and treat them accordingly. The

MEASURES FOR INSECT CONTROL 315

weevils are reckoned invariably as plant feeders, almost
entirely confined to fruit or seeds, while CardbidcB, though
largely carnivorous, show too much variation in food and
too many herbivorous species to make it safe to draw con-
clusions without the study of each species. In the applica-
tion of this principle, therefore, it becomes necessary to
consider the nature of the group as a whole, not merely
the habits of certain ones.

MEASURES FOR INSECT CONTROL.

There have been a great many different remedies and
plans of treatment for the control of injurious insects and it
would be impossible to discuss them all, even those which
have general application, in a short course. The attempt
will be to select some of the most universal and useful and
give them with such rules as to make it possible to apply
them without further instruction.

In general the methods of control for insects may be
separated into those which are direct and have in view the
destruction of the insect with some destructive agent or
mechanical application, and those methods that depend upon
some plan of cultivation or sequence of crops to prevent or
modify the insect attack.

Direct Methods. Insecticides. — Substances used in such
manner as to kill directly are termed insecticides, and insec-
ticides may be classed broadly into two large groups: (1)
those which are poisonous in character and depend for their
effect upon the insects swallowing them with their food and
(2) those which affect the insects by contact or penetration,
such as the oils and fumigants.

Of the poisonous materials some preparations that are
among the most important may be mentioned.

Paris Green.— Paris green is a bright green arsenical
powder which should contain at least 50 per cent, arsenious
oxide and not over 3.5 per cent, soluble arsenic. The for-
mula^ for its use are as follows:

Paris green 5 ounces

Lump lime 1 pound

Water 50 gallons

316 PRINCIPLES OF ECONOMIC ENTOMOLOGY
For small quantities use:

Paris green 1 heaping teaspoonful

Lump lime 2 or 3 ounces

Water 3 gallons

For dry application the powdered Paris green may be
mixed with flour or air-slaked lime and dusted upon the
plants by enclosing the powder in a muslin sack and shaking
this over the plants it is desired to treat.

London purple is a by-product in the manufacture of
aniline dye and is an effective poison but somewhat less
certain in its effect and more likely to injure foliage. It is
at ])resent not so common on the market as Paris green, it
is, however, somewhat cheaper and when properly diluted
is a desirable insecticide.

Arsenate of Lead. — Arsenate of lead, available in two forms
— paste or as a white powder — may be secured on the market,
or the arsenate may be formed by chemical combination of
arsenic and lead. Formulse for the use of this substance
are as follows:

Arsenate of lead (paste) 3 to 10 pounds

Water 50 gallons

or

Arsenate of lead (powder) 1 to 4 pounds

Water 50 gallons

For small quantities use:

Arsenate of lead (paste) 1 teaspoonful

Water 1 gallon

If used as a spray this can be applied to a great variety of
plants for the destruction of leaf-eating insects, and since
it can be used at high strength without injury to foliage it
may be used for the most resistant kind of insects. Its killing
power is not equal to that of Paris green and consequently
somewhat stronger solutions must be used.

Like Paris green, it may be used in the dr}' form as dust
or with a powder gun.

Hellebore. — Hellebore is a white powder destructive to
insects but not poisonous to domestic animals or man, unless

MEASURES FOR INSECT CONTROL 317

in large doses. It may be used as a spray or in a dry form
and is applicable to currant bushes or other kinds of fruit,
for saw-fly larvte and other leaf-feeding insects where it is
undesirable to use arsenic.

Arsenical Bran Mash. — This is used as a bait for cut worms
and other insects which endanger vegetation and which it is
desirable to kill before the vegetation has been attacked.
Formula as follows:

Bran 25 pounds

Paris green ^ pound

Cheap molasses 1 quart

Water, as needed to moisten.

For small quantities use:

Bran 1 quart

Paris green 1 teaspoonful

Cheap molasses 1 tablespoon ful

Water, as needed to moisten.

For grasshoppers the attractiveness of this bait is very
much increased by the addition of lime juice or orange or
lemon flavor.

Contact Insecticides. — Insecticides of this group depend
upon immediate contact with the insects to be affected, .
different kinds of sprays, direct applications and the use of
fumigants which are distributed to the insects to be reached.

Lime-sulphur wash is the most important of the insecti-
cides now in use against the scale insects, especially the
San Jose scale. The commercial lime-sulphur preparations
on the market generally may be secured at seed-stores
or from dealers in nursery or orchard supplies and depended
upon as containing the correct proportions and if used
according to directions should give very certain results.
These can be secured at reasonable prices and are often
preferable to the solutions of home preparation. How-
ever, directions for the preparation of the compound may be
of service and two formula? will be given, one for the concen-
trated solution to be diluted when used and the other for
immediate use.

318 PRINCIPLES OF ECONOMIC ENTOMOLOGY

Fig. 251.— Plant for making lime-sulphur solution in large quantities.
(Photo. Ohio Exp. Sta.)

Concentrated Lime-sulphur.

Lump lime 50 pounds

Sulphur 100 pounds

Water (hot) 70 gallons

Dilute as directed.

MEASURES FOR INSECT CONTROL 319

For exact preparation the use of the hydrometer is desir-
able and the following scale of proportions is recommended.

Reading on hydrometer Number of gallons of water to 1 gallon

in degrees (Baum6). of the concentrated lime-sulphur.

35 9

34 8f

33 8i

32 8

31 7h

30 7i

29 6f

2S 6^

27 6

2(i 5f

25 5i

24 5

23 4j

22 4i

21 3f

20 3i

19 3i

18 3

17 2|

16 2|

15 2i

14 2

Reijular Lime-sulphur Wash (for winter spray).

Lump lime 20 pounds

Sulphur 12 pounds

Water 50 gallons

Kerosene. — The use of kerosene or petroleum combinations
has o;i\'en some of the most useful combinations and they
still have a wide range of usefulness, although at present
less used than the lime-sulphur solutions for scale insects.
Generally they may be applied to practically all kinds of
insects which are suctorial in habit and cannot be reached
by arsenical sprays, but they are especially efficient against
the scale insects at time of migration and against such soft-
bodied insects as the plant lice. In the preparation of the
kerosene emulsion it is extremely important that a thorough
emulsion be obtained so there will be no separation of oil
from the water, as there is much damage to the foliage if
this occurs.

320 PRINCIPLES OF ECONOMIC ENTOMOLOGY

The standard formula for kerosene emulsion is as follows:

Hard soap | pound

Hot water (soft) 1 gallon

Kerosene (coal oil) 2 gallons

To form the emulsion take a gallon of soft water and
dissolve in it a half-pound of soap, then remove from fire,
add two gallons of kerosene, which should be thoroughly
mixed and agitated at once. One of the best methods is to
run the solution through a spray pump, driving it back into
the bucket from which the solution is drawn, and about
five or six minutes of this mixing will produce a perfect emul-
sion. It should be carried to such completion that there
will be no tendency for the oil to separate. Small quantities
may be made rapidly in the proper proportions by ihe use of
an egg-beater or by a process which produces a violent
agitation w^hich may be maintained for some length of time.
This strong emulsion should be kept in a cool place and
covered or in a tight receptacle and may be diluted as wanted
with soft w^ater, the amount of dilution depending upon the
insects to be reached. For scale insects, one pint of strong
emulsion to nine parts water. Soft plant lice are readily
killed by a solution of one part of stock solution to fifteen
parts of water.

Tobacco Extract.— This is a very efficient contact insecti-
cide and may be used against many kinds of insects but
especially such forms as plant lice, thrips, and the better-
protected sucking insects. Various solutions are on the
market but the one termed Black Leaf 40, containing 40
per cent, nicotine sulphate, is one which seems to have
proved one of the best; this is used in dilutions of 1 part
to 300 of water to 1 part to 600 parts of water — for use in
winter time, when plants are dormant, and for summer use,
dilutions — 1 to 500, to 1 to 1000 are recommended for tender
insects such as plant lice. Similar solutions may be used for
parasitic lice and mites on domestic animals.

Tobacco dust may be used or an extract prepared from
this by steeping or soaking in water overnight. In making
the preparation boil one pound of dust or stems to a gallon

MEASURES FOR INSECT CONTROL

321

of water, and this may be diluted, one to two parts of water
and ap])lied for leaf-sucking insects.

Pyrethrum or Persian Insect Powder. — This is a very power-
ful insecticide when properly prc])ared, but loses its strength
when exposed to air, so that particular care should be taken
to keep it in a tightly closed receptacle or it must be used
when quite fresh. It is a powdered material derived from the
grinding of the leaves or flowers and buds of the Pyrethrum
plant, the main sup])ly coming from Dalmatia, buta consider-

able amount being produced in California. It is a volatile
oil and it is the vaporization and contact of this which is
destructive to the insect. It may be used as a spray by the
dilution of one ounce of powder to two gallons of water, and
is available for saw-fly larvae and other pests upon currants,
gooseberries, etc., being especially valuable on account of
its not being poisonous to man or domestic animals. The
powder, blown into rooms is effective for the killing of
mosquitoes and flies, but for this i)urpose does not compete
21

322 PRINCIPLES OF ECONOMIC ENTOMOLOGY

with some other measures. It may be used upon dogs and
cats for the kilhng of fleas by dusting in the hair.

Machinery. — For the appHcation of these various insecti-
cides, a great many forms of spraying outfits, dusting
machines, etc., have been devised. These are now so thor-
oughly standardized and handled by reputable firms that
anyone may secure such outfits as may be needed for his
individual purpose.

Cultural Methods. — iVnother distinct group of measures
for insect control (the indirect methods) may include those
which have to do with methods of culture and alternation of
crops and ^'arious cultural methods which incidentally have
an effect upon the activities of insects.

First among these may be mentioned the general practice
of crop rotation which for a good many insects serves in an
admirable way to prevent undue multiplication of injurious
forms. Aside from its advantages in other waj's, rotation
serves to dislodge or starve out a great number of insects
which are not able to migrate readily and which become
established in any field only after several years of uninter-
rupted development. For such forms the plowing up of the
fields or a change from one crop to another may prove an
almost perfect control. A striking example of this has been
noted in the case of the corn-root worm. In somewhat les-
ser degree the process is available for many of the pasture
and meadow insects which are dependent upon grasses as
their main food supply and which when grass is plowed
under, especially if this is done at a time when the insects
are in larval or in a known migratory stage, serves to destroy
them very effectively.

In a general way plowing will cut off the food supply, some-
times will bury the insects to such a depth that they do not
extricate themselves. In this connection, however, it is some-
times very important that the condition of the insects be
known, as there are cases, such as white grubs, sod worms,
and wire worms, which if plowed under with the sod will,
if a second crop is planted soon, transfer their attack to the
new crop with very disastrous consequences. It frequently

MEASURES FOR INSECT CONTROL 323

happens that corn planted on sod land is in this way very
seriously injured. The precaution should be to plow under
long enough before the new crop is planted to allow oppor-
tunity for the starving out of insects which may be present
in the grass.

Another practise in this line is for such an arrangement of
crops that insects which naturally migrate from one crop to
another will be sejjarated by a crop of different character,
something that will not serve them as a food supply. For
instance, the migration of the chinch bug from wheat fields
into corn fields may be prevented by the introduction of a
strip planted to potatoes, beans or some crop which is not
available as chinch bug food.

The use of an early planted crop for the purpose of attract-
ing insect egg deposition wuth the view of destroying the
insects so attracted and thus protecting the later crop, has
been in vogue for many years and is applicable to such
species as have several generations in a season. A good
example of this is the corn-ear worm which if attracted to
a small area of early planted corn which is fed to hogs at the
time the worms begin work will assist much in the preven-
tion of attacks on adjacent fields.

In some cases where an insect is especially destructive in
a certain area, resort may be had to the suppression of the
cultivation of a crop for one or two seasons, thus eliminating
food. This will largely diminish if not practically extermi-
nate such insects as are strictly dependent upon this crop for
existence. Naturally such a method is limited in application,
as the complete suppression of any crop in a certain district
is a difficult matter to accomplish.

Clean culture is often recommended as an important
aid in the suppression of insects, and there is no doubt that
for many species attention to the elimination of food plants
which assist them to survive and the cleaning up of litter
in which they may hibernate will accomplish a great deal
in the reduction of numbers and the consequent extent of
injury. Clean culture, however, must be taken in connec-
tion with a study of the habits of the species wdiich it is

324 PRINCIPLES OF ECONOMIC ENTOMOLOGY

desired to control and cannot be considered as an efficient
practise for many insects that are troublesome on the
average farm. In this connection it may be stated that it
is good entomological practise to use wire fences in place
of the old rail or board fences, and it is a good plan to culti-
vate as close as possible to fence lines with the consequent
reduction of the growth of weeds, bushes, and so on.

Another matter which deserves attention is a close guard-
ing against the introduction of pests in seed or along with
introduced plants, as many of the serious pests are readily
transferred from place to place in such materials as straw
and various kinds of seed packages and thus gain a foot-
hold in a locality in which they ha\e not been troublesome
before.

NATURAL ENEMIES.

Insects are preyed upon l)y many natural enemies — birds,
reptiles, toads, spiders, and these serve as checks to their
inordinate increase. Bird protection has been strongly
urged as an aid in insect control and certainly all or nearly
all of our common field birds are best allowed all the pro-
tection possible. Especially the small insectivorous birds
such as wrens, swallows, chickadees, titmice, etc., should be
given all the protection possible. Spiders are also generally
useful rather than injurious and should be undisturbed.

PREDACEOUS AND PARASITIC INSECTS.

The position of the ]:»redaceous and parasitic insects is one
of considerable complexity, since their attacks may be
directed against both injurious and beneficial forms, and
their relation to human interests depends, of course, upon
the nature of the insects which they attack. In a general
way the carnivorous species feed upon the herbivorous ones,
and the herbivorous ones being ordinarily the most destruc-
tive to valuable crops, the average result may be looked
upon as advantageous. The study of these natural enemies
of the injurious insects has formed a considerable part of

PREDACEOUS AND PARASITIC INSECTS 325

economic entomology, and the imi)ortiince of the subject
has been pretty generally recognized, though different
workers have assigned quite different vahie or importance to
to the subject.

Predaceous insects are those which attack and devour
other insects, possibly quite different kinds of insects, and
do it without sacrificing their own activity or independence.
Parasitic insects, using this term as it applies more particu-
larly to economic entomology, are those which are dependent
for a larger or smaller part of their existence upon some
particular kind of insect host. Nearly all are internal
parasites and in a great majority of cases the entire develop-
ment of the individual from the egg to pupa or adult stage
is passed within the body of a single individual host. Some-
times a large number of individuals will develop within a
single host, as in case of the minute ichneumons which
parasitize the larger caterpillars.

It must be noted here that a parasite itself may be para-
sitized by another species called a "secondary" parasite
which, by reducing the numbers of the parasitic species,
would become from the economic stand-point injurious.
This, again, in some instances may support still another
parasite, a so-called "tertiary" parasite, which by reducing
the numbers of the secondary parasite would be detrimental,
and a fourth, where such occurs, again assumes the opposite
role. It is evident where such a complex condition of para-
sites exists that it is practically impossible to adopt any
means of encouraging the beneficial or destroying the inju-
rious ones, and that this complex system of wheels within
wheels must be allowed to work out its own conclusion in the
balance of nature.

For most species there is perhaps but little that can be
done in the way of preserving the beneficial parasites or of
facilitating their work. We simply allow them to go on un-
molested, serving so far as they may, as a natural check upon
the injurious species. Many of our destructive insects are
insects that without this check would be seriously destruc-
tive, the regular attacks of these ])arasites serving very

326 PRINCIPLES OF ECONOMIC ENTOMOLOGY

effectively to keep the destructive species in reasonable
bounds and often preventing it from causing any serious
loss. The Hessian fly is certainly kept in check during a
considerable portion of the time by just such agencies, and
we can scarcely doubt that if the parasites of this species
were eliminated and other conditions unaffected, the losses
incurred would be enormously increased.

With some species it may be possible to assist the para-
sitic forms or to preserve them in such manner as to get the
advantage of their service. For instance, the cabbage
l)utterfly is very commonly parasitized by a small ichneu-
monitl {Ftcromahis) which issues from the pupa?, and it is
evident that if the pupse were gathered and instead of being
crushed were enclosed in wire screen of such mesh as to
retain the issuing butterflies but allow the free escape of
the minute parasites, there would be a destruction of the
healthy butterflies without any reduction in the numbers of
the parasites. Again, in the case of the Hessian fly, care
as to the time when the stubble is burned or plowed under
in order to allow opportunity for escape and survival of
the ])arasites, might be of special service in their protection.
In California extensive shipments of lady l)ugs from the
northern part of the State to the Imperial valley to prey
upon the plant lice affecting melons is claimed to have
accomplished much in their control.

On the whole, however, the utilization of parasites in a
direct manner can hardly be depended upon as a very great
advantage, especially because of the difficulty in so training
the average cultivator that he will be able to distinguish
between parasites and non-parasitic forms, and adapt his
practice to accommodate them.

A more important phase of the subject perhaps is found
in the transportation of parasitic species from one country
to another where an injurious species has been introduced
without the introduction of its native enemy. It has already
been suggested that the original habitat of an injurious
insect is a matter of great importance, especially with
reference to its natural parasites, and a number of instances

EXCLUSION AND RESTRICTION 327

are now in evidence showing the possibihty of controUing
injurious, introduced species by means of the introduction of
the native enemies. The most conspicuous is that of the
cottony cushion scale, introduced into Cahfornia 'several
years ago, and in more recent years the very extensive intro-
duction of predaceous and parasitic enemies of the Gipsy
and brown-tail moths in the New England States for the
control of these very destructive imported pests.

EXCLUSION AND RESTRICTION.

These are most important means of controlling insect
depredations. Formerly the entomologist devoted his
entire attention and effort to the study of native species
but now his attention is largely directed toward exclusion
from and restriction in the United States of new insects.
Until recently in the introduction of new plants from foreign
countries, no attention has been paid to the new insects
introduced with them. An important part of the work of
the entomologist in the future will be to study the insects
of other countries — not only those that are now destructive
there but those that do no particular damage, yet when
the natural checks are removed, are likely to become
destructive.

Special attention must be paid to those insects which are
native in those countries from which we import a greater
part of our plants. Some of the foundation principles in the
study are :

1. An insect, coming from another country, is more likely
to become destructive here if it comes from a somewhat
similar climate, and if the food plants are somewhat closely
related to those of its native country.

2. Insects coming from different climates may, if they have
a wide range of food plants, adapt themselves to the new
climate. It will then be proper to consider tropical species,
especially if their food plants are widely distributed and
have nearly related species in the country to which they are
brought.

328 PRINCIPLES OF ECONOMIC ENTOMOLOGY

3. Tropical insects that are limited to tropical plants for
food, will have little importance in temperate regions except
in greenhouses.

]\Iost of the scale insects are tropical and in this climate
are on the borderline of their destructive region, hut on
account of their general food habits they constitute a general
pest.

The question of the control of the distribution of the
destructive species is yet a new problem and one over which
there is considerable dispute; any measure intended to exclude
a foreign species must be adapted to a particular species, as
a general law will not suffice. Even the general exclusion of
the foofl plant will not alone be effective in keeping out the
pest, as it may have other means of dispersal.

Inspection and enforcement of restrictions at the port of
entry are being quite generally adopted. Inspection is most
effective when applied to plants. Sometimes it is necessary to
introduce a foreign species to prey on another foreign insect
that is already here, as was the case with cottony cushion
scale in California.

GLOSSARY OF THE TERMS USED IN
ENTO:\IOLOGY.

Abdomen. The posterior region of the insect body.

Abiogenesis. Spontaneous generation.

Abraded. Scraped or rubbed.

AcALYPTRATA. Those muscid flies in which aUilix' are absent or
rudimentary.

Aculeate. Prickly; armed with a sting.

Acuminate. Tapering to a long point.

Addorsal. Close to but not on the middle of the dorsum.

Adephagous. Belonging to the .Xdcphaga; pentamerous, predatory,
terrestrial beetles with filiform aiitcmui'.

Adpressed. Contiguous or prcs.scd to.

Agamic. Reproducing without union with a male.

Agamogenesis. Reproduction without fertilization by a male;
parthenogenesis.

Agglutinate. Glued together in a mass.

Aggregated. Crowded together.

Ala (pi. Al.e). Wing or wings.

Alary. Relating to wings.

Alate. Winged.

Alternation of Generations. Periodic production of partheno-
genetic females in a species that occurs in both sexes. These females
produce both sexes. Examples occur in Cynipidse and in some
Homoptera.

Alul.e. a pair of membranous scales above the halteres, behind the
root of the wing, one above or before the other; the anterior attached
to the wing and moving with it, the posterior fastened to the thorax
and stationary. Occm-s in Diptera. Synonyms calyptra; squama;
squamula; lobulus; axillary lobe; aileron; scale; tegula?. In Cole-
optera, a membranous appendage of the elytra which prevents
dislocation.

Alulet. The lobe at basal portion of wing in Diptera.

Ametabola. Insects not having obvious metamorphosis, the larvae
resembling the adult and the pupa? being active.

Amnion. The inner of the two membranes enclosing the embryo.

Amphimixis. The mingling of the germ plasm of two individuals.

Ampulla. In Orthoptera, an extensile sac between the head and
prothorax, used by the young in escaping from the ootheca, and later
in moulting. In Heteroptera, a blister-like enlargement at the middle
of the anterior margin of the prothorax.

Anal. Pertaining or attached to the last segment of the abdomen.

Anal angle. That angle on the secondaries nearest the end of the
abdomen when the wings are expanded. The angle between the inner
and outer margin of any wing.

( 329 )

330 GLOSSARY OF TERMS USED IN ENTOMOLOGY

Anal appendages. The external genital parts.

Anal area. In Orthoptera and Neuroptera, the hinder or anal
portion of a wing within the anal vein.

Anal field. That area on the tegmina of Orthoptera corresponding
to the anal area of the secondaries.

Anal plate. In caterpillars, the shield-like covering of the dorsum
of the last segment.

Annulate. Marked with colored rings or bands.

Annulus. a ring.

Ante-apical. Before or in front of the apex.

Antenna. Two-jointed organs of sensation situated on the head.

Antepectus. The lower surface of the prothorax.

Antigeny. Sexual diversity.

Anus. The posterior opening of the digestive tract.

Apex. The terminal portion of any organ of body, the part farthest
away from the base.

Appendiculate. Bearing appendages.

Appendix. A part added or attached to another part.

Apterous. Without wings.

Aquatic. Living in the water.

Araneiform. Spider-like in appearance.

Arboreal. Living in or on trees.

Arborescent. Branching.

Arcuate. Bowed or curved.

Arenose. Sandy, not smooth.

Areola. A small cell on the wings of certain Hemiptera.

Arista. A specialized bristle or process on the antenna of certain
Diptera.

Arolium. Cushion-like pads on the tarsi of many insects.

Arthropoda. Jointed animals having jointed appendages.

Articulate. Divided into distinct joints.

Articulation. Joint; place where two joints meet.

Asexual. Without sex. Reproduction which does not involve the
union of individuals of different sexes. Reproduction by budding, etc.

Ater. Deep black.

Atomarius. With minute points or dots.

Bifid. Split, two parts.

Bifurcate. Divided; forked.

Bionomics. The habits, breeding, and adaptations of living forms.

Biserrate. Saw- toothed on two edges.

BiviTTATE. Having two longitudinal stripes.

Brachycerous. Having short three-jointed antenna?, Diptera.

Brachypterous. Short-winged.

Bristle. A short, stiff hair.

Buccal. Relating to the mouth cavity.

Bulla. A blister or blister-like structure.

CiECUM. A blind sac or tube opening into the alimentary canal.
Calypter. In Diptera, the alula when it covers the haltere.
Campodeiform. Resembling campodea.

Canaliculate. Grooved longitudinally, with a concave line in the
middle.

GLOSSARY OF TERMS USED IN ENTOMOLOGY 331

Cancellate. Cross-barred; latticed.

Capillary. Hair-like; long and slender.

Capitate. Terminating in a little head or knob.

Caprification. Process of fertilization of Smyrna figs by Blasto-
phaga through the medium of "caprifigs."

Carabidoid. Resembling a Carabid.

Carina. An elevated ridge.

Carnivorous. Flesh-eating.

Cauda. The tail; any process resembling a tail.

Caudad. Toward the posterior region of the body.

Caudal. Pertaining to the posterior end of the body.

Caudal set.e. Tlu-ead-like processes at the end of the abdomen.

Caudate. Having tail-like extensions.

Caverniculous. Cave-inhabiting.

Cell. Space within the veins on the wing.

Cellule. A small space included between the veins on the wing.

Cephalad. Toward the head.

Cephalic. Belonging to the head.

Cervical. Relating to the neck.

Chaetotaxy. The science dealing with the arrangement and
nomenclature of the bristles on the body of insects.

Chelate. Having a claw.

Chitin. The material of which the hard parts of the insect body are
formed.

Chitinous. Composed of chitin or similar to chitin.

Chrysalis — id. The intermediate stage between larva and adult;
see pupa.

Cicatrix. A scar; an elevated, rigid spot.

Cilia. Fringes.

Ciliate. Fringed; set with parallel hairs or bristles.

Clasper. a chitinized process, free or attached to the inner sides
of valves or other lateral pieces and serving to hold the female parts
during copulation; the harpes.

Claval suture. Indentation separating the clavus at the base of
the hemelytra in Hemiptera.

Clavate. Club-shaped; thickening gradually toward end.

Clypeus. The anterior median portion of the head to which the
labrum is usually attached.

Coarctate. Contracted; compact.

Cocoon. Silky covering enclosing pupa,

CoLLUM. The neck or collar.

Colon. The large intestine.

Connate. United at base, or along the whole length.

CoNNEXivuM. The prominent abdominal margin of Heteroptera at
junction of dorsal and ventral plates.

Coprophagus. Feeding on excrement on or decaying vegetable
matter of an excrementitious character.

Cordate. Heart-shaped.

Coriaceous. Leather-like.

CoRiUM. The elongate middle section of the hemelytra which
extends from base to membrane below the embolium.

Cornicles. The honey-tubes in plant lice.

332 GLOSSARY OF TERMS USED IN ENTOMOLOGY

Costa. An elevated ridge that is rounded at its crest; the thickened
anterior margin of a wing.

Costal area. The area behind the costal vein.

Costal cell. The area inclosed between the costal and subcostal
veins.

Coxa. The basal segment of the leg.

Coxal cavity. The opening or space in which the coxa articulates.

Crenate. Scalloped.

Crepuscular. Active at dusk.

Cristate. Crested.

Dentate. Toothed.

Dentate-serrate. Tooth-serrated: the denticulations themselves
being serrated on then- edges.

DicHOPTic. Eyes separated by front, not contiguous.

DicHOTOMOus. Forked, dividing by paii's.

Dimorphic. Occurring in two well-marked forms.

Dimorphism. A difference in form, color, etc., between individuals
of the same species, characterizing two distinct types.

Dioecious. Having distinct sexes.

Discal. On or relating to the disk of any surface or structure.

DisTAD. Toward the distal end.

Distal. That part of a joint farthest from the body.

Divergent. Spreading out from a common base.

Dominant. A character more constant and conspicuous than any
other.

Dorsad. Toward the upper surface.

Dorsal. Of the back.

Dorsum. The upper surface.

Drone. The male bee in Hymenoptera.

Ecaudate. Without tails or tail-like processes.

EcDYSis. Moulting or casting of the skin.

Ecology. The science of the relation of organisms to each other
and to their surroundings.

EcTAD. Extending outwardly from within.

EcTAL. Relating to the outer surface.

Elytra. The anterior leathery or chitinous wings of beetles.

Embolium. The narrow sclerite extending along the anterior margin
of the hemelytra, from base to cuneus or membrane, in Heteroptera.

Empodium. The small process between the pulvilli in Diptera.
The bifid pseudotarsi between the claws in Coleoptera.

Ensiform. Sword-shaped.

Entad. Extending inwardly.

Ental. Pertaining to the centre of the body cavity.

Entire. With an even, unbroken margin.

Entomogenous. Growing in or on an insect.

Entomophagous. Insect-feeding.

Episternum. The anterior and larger lateral thoracic sclerite
between the sternum and notum.

Epizoa. Insects that infest the body surface of animals.

Ergatoid. Wingless ants, sexually developed.

GLOSSARY OF TERMS USED IN ENTOMOLOGY 333

Eruciform. Caterpillar-like in appearance.

Exotic. An introduced species, not native to the place foun<l.

ExsERTED. Protruded.

Facet. One of the small divisions of the conii)oinid eye.
Fasciate. Banded.

Femur (pi. femora). The thigh between the coxa and tibia.
Filiform. Thread-like.

Flabellate. With long, flat processes folding like a fan.
Formic. Pertaining to or derived from ants.
Formicary. An ant's nest or ant hill.

Front. Anterior portion of the head between the base of antenna;
and below the ocelli.
FuMOSE. Smoky.

FuNGicoLous. Living in or on fungi.
FuRCA. A fork or forked process.
Furcate. Forked.
Fuscous. Very dark brown.

Gena. Cheek; that portion of the head below the eyes on each side
extending to the gular suture.
Generation. Brood.

Genitalia. External organs of reproduction and their appendages.
Granulated. Covered with small grains.
Gregarious. Living in groups or communities.
Griseus. Light gray.
Guttate. Spotted, light spots on dark ground.

Habitat. The locality in which an insect lives.

Haustellate. Formed for sucking.

Haustellum. Sucker; the part of the mouth through which liquids
are sucked.

Hermaphrodite. A bisexual individual.

Heterogamy. Alternation of generations, two sexual or a sexual
and a parthenogenetic.

Hibernaculum. a tent or sheath in which a larva hibernates.

Hibernate. To pass the winter in a dormant condition.

Hypermetamorphosis. The case in which an insect passes through
more than the normal stages of development.

Hyperparasite. a parasite that is parasitic upon another jiarasite.

Imaginal Pertaining to the adult or imago.
Imago. The adult or sexually mature insect.
Infumated. Clouded.

Infuscated. Smoky gray-brown, with a blackish tinge.
Inquiline. a species living in a gall made by another species, not
as a parasite but as a guest.

Inquilinous. Living as guests in the homes of others.
Insectary. a place where insects are bred for the purpose of study .
Instar. The period or stage between moults in the larva.
Integument. The outer covering to the insect body.
Intima. The lining membrane of the trachea.

334 GLOSSARY OF TERMS USED IN ENTOMOLOGY

Invaginate. When a tubular or vesicular part is turned inward or
retracted within the body wall.

Iridescent. Reflecting the prismatic colors.

Iris. The circle which, in an ocellate spot surrounds the pupil.

Irrorate. Marked with fine points.

Iso. Equal.

JuGA. The lateral anterior lobes of a Hcteropteron ; each side of
the tylus.

Labellum. The sensitive ridge tip of the mouth structures of
certain Diptera; a prolongation of the base of the rostrum in Coleoptera
and Hemiptera.

Labial. Pertaining to the labium.

Labium. The lower lip.

Labrum. The upper lip.

Lacinia. The inner lobe of the first maxilla, articulated to the stipes,
bearing brushes of hairs or spines.

Lacun.e. Irregular cavities.

Lamella. A thin plate.

Lamellate. Divided laterally into distinct leaf-like plates.

Lanceolate. Spear-shaped.

Larva. The second stage in the development of the insect, follows
immediately after the egg stage.

Larvarium. The shelter-case of the larva.

Laterad. Toward the side and away from the median line.

Lateral. On the side.

Littoral. Living along the seacoast or in the shore debris.

LoRA. The chitinous bands connecting the submentum with the
cardo of the maxilla.

Lumen. The cavity or hollow part of an organ or tube.

Lunula. A small crescent-shaped mark.

LuNULE. A lunate mark or crescent.

Macroch^t.e. The long bristles occurring singly on the body of
Diptera.

Macropterous. Long or large winged.

Macula. A colored mark larger than a spot and of no definite shape.

Maggot. The footless larva of Diptera.

Mammilate. With nipple-like protuberances.

Mandible. The lateral upper jaws of a biting insect.

Mandibulate. Having jaws or mandibles.

Maxilla. Jaws; one on each side of the mouth immediately
beneath the mandibles.

Maxillary . Belonging to the maxilla.

Meconium. The substance excreted by certain metabolic insects
soon after their emergence from the chrysalis.

Mediad. Toward the middle.

Medial. Referring to or at the middle.

Median. Middle.

Melanic. Blackish.

GLOSSARY OF TERMS USED IN ENTOMOLOGY 335

Melanism. An abnormal darkening.

Mellifera. Honey-makers.

Mbntum. a labial sclerite bearing the movable parts.

Mesenteron. The middle portion of the primitive intestinal canal ;
the midgut.

Meso-. Middle.

Mesonotum. The primitively upper surface of the middle thoracic
ring.

Meta-. Posterior.

Metabolism. Transformation, changes of food into tissue and of
tissue into waste products.

Metanotum. The primitively upper sm'face of the third or posterior
thoracic ring.

Metathorax. The third thoracic ring or segment.

Metopidium. The anterior declivous sm-face of prothorax in Mem-
bracidae.

MiCROCH^T^. Small bristles, as opposed to macrochsetse, in Diptera.

Micron. The unit of microscopic measurement.

Mimetic. Mimicry of appearance but not structure.

Mimicry. The resemblance of one animal to another not closely
related.

Monoecious. The combining of both sexual elements in one indi-
vidual.

Moult. The transformation of a larva from one instar to another;
the cast skin of a larva that has moulted.

Nearctic. Temperate and arctic North America, including Green-
land.

Necrophagous. Living in or on carrion.

Nectaries. Honey-tubes.

Neotropical. That part of the earth's surface embraced in the
greater part of Mexico, West Indies and South America.

Nocturnal. Night-flying.

Obsolete. Indistinct, nearly or entirely lost.

Obtect. Wrapped in a hard covering.

( )btected. Covered with a chitinous case which conceals appendages
but through which their outlines are revealed.

(Ocelli. Plural of ocellus.

Ocellus. A simple eye.

Ontogeny. The development of the individual as distinguished from
that of the species.

Ootheca. The covering of an egg mass.

Operculum. A lid.

Optic. Relating to the organs of vision.

Oral. Pertaining to the mouth.

Oriental. In geographical zoology as used by Wallace, that part of
the earth's surface including Asia east of the Indus River, south of the
Himalayas and the Yangtse-kiang watershed, Ceylon, Sumatra, Java,
and the Philippines.

Ova. Eggs.

336 GLOSSARY OF TERMS USED IN ENTOMOLOGY

Ovum. An egg.

OviPosiTioN. The act of depositing the eggs.

Ovipositor. The structiu-e by means of which the eggs are placed.

PjEDOGenesis. Reproduction in tlie larval stage.

Palearctic. Relating to that part of the earth's surface including
Em-ope, Africa north of Sahara, and Asia as far as the southern edge of
the Yangtse-kiang watershed and the Himalayas, and west to the Indus
River.

Pallid. Pale.

Palmate. Like the palm of the hand with finger-like processes.

Palpus. Articulated moveable appendage in the mouth of insects.

Parasitic. Living on or in another animal or insect and dependent
on the host for food and support.

Parthenogenesis. Reproduction by direct growth of germs from
egg-cells without fertilization by the male.

Parthenogenetic. See asexual.

Pectus. The ventral portion of the thorax.

Pelagic. Living in the open sea.

Pellucid. Colored, but transparent; sometimes no color.

Petiolate. Placed on a stalk.

Phylogeny. The developmental relationship of a genus, family, or
other group.

Pile. A fur-like covering.

PiLiFERous. Having a covering of j^ile.

Plicate. Folded hke a fan, plaited.

Plumose. Feathered, like a plume.

PoLLiNOSE. Covered with a pollen-like dust.

Polyandry. Mating of one female with more than one male.

Polyembryony. Product k )ii i if mm ire than one embryo from one egg.

Polygamy. Mating of one niiile with more than one female.

Posterior. Hinder or hindcrmost; opposed to anterior.

Predaceous. Living upon other organisms.

Predatory. Predaceous.

Primaries. The anterior or fore-wings.

Primitive. Simple in character; of an early or ancient type.

Pro-. Anterior to.

Proboscis. The extended mouth structure.

Proximad. Toward the proximal end.

Proximal. That part of an appendage nearest the body.

Pruinose. Hoary, covered with fine dust.

Pseudimago. Subimago.

Pseud- or pseudo-. Prefix meaning false.

Pseudogyne. a female that reproduces without impregnation.

Pseudova. Egg-hke germ cells capable of development without
fertilization.

PuLVERt^LENT. Powdcry.

Pupa. The intermediate stage between larva and adult.

Puparium. The thickened larval skin within which the jnipa is
formed.

Pupate. To become a pupa.

Pupation. Becoming a pupa.

GLOSSARY OF TERMS USED IN ENTOMOLOGY :537

Pygidium. The last dorsal segment left exposed by the elytra.
Pygofer. The last segment of the abdomen in certain Homoptera,
^'specially the lateral margins which appear in ventral view.

Radial. Pertaining to the radius or radial vein.
Rostrum. A snout-like i)rolongation of the head.

ScABER. Rough, uneven.

Scape. The second articulation of the antenna^, often elongateil.

Scutum. The second dorsal sclerite of the meso- and metathorax.

Sensoria. The circular openings covered by membrane on the
antennae or legs of plant lice.

Serrate. Like the teeth of a common saw.

Sessile. Closely attached.

Setaceous. Bristle-shaped, slender, tapering.

Social. Living in communities.

Spermatogenesis. Development of the spermatozoa.

Spinneret. Any organ consisting of an internal tube, terminating
in a pore, spine or process, producing a silky or waxy fiber.

Spiracle. A breathing pore opening to the trachea.

Stage. A period in the course of development.

Stellate. Star-shaped.

Sterile. Incapable of reproduction.

Sternite. The ventral piece in a ring or segment.

Subimago. The stage in ephemerids and some other insects just
after emergence from the pupa and before the final moult during flight.

Tenent hair. Specialized hair adapted for clinging or clasping.

Teneral. That state of the imago just after its exclusion from pupa
or nymph, in which neither coloring nor clothing is fully developed.

Teres, terete. Cylindrical.

Tergal. Belonging to the primitively upper surface.

Thorax. The second or middle portion of the insect body, bearing
the true legs and wings; made up of three sections, the pro-, meso-
and metathorax.

Trachea — .e. The breathing tubes of insects.

Tracheate. Supplied with a trachea.

Tracheoles. The capillary trachea of the adult as they develop
in masses in the larva; very small, slender tracheae.

Transition zone. The transcontinental belt in which the austral
and boreal elements overlap; it is divided into a humid or Alleghanian-
area, a western arid area, and a Pacific coast humid area.

Trochantine. The basal part of the trochanter when it is two-
jointed.

Tumid. Swollen.

Tylus. The anterior central lobe of the head in Hemiptera.

Unicolorous. Of one color throughout.

\'aginate. Inclosed in a bivalved sheath.

\'alve or \'AL^■UL.E. The expanded plate-like galea of the maxilla in
many Hymenoptera.

338 GLOSSARY OF TERMS USED IN ENTOMOLOGY

Valve. A small, transverse or triangular piece behind the last full
ventral segment, at the base of plates in male Jassidte and allies.

Venation. The system of chitinous framework supporting the wings.

Venter. The inferior or under portion of the abdomen.

Vestigial. Undeveloped or degenerate; the trace or remnant of a
previously functional organ.

Vestiture. The surface covering.

Viscera. The internal organs of the body.

Visceral. Pertaining to the viscera.

Vitta. a longitudinal, colored line.

Vittate. Striped.

Viviparous. Bearing living young.

Wing pads Undeveloped wings of pupa or nymph.

INDEX.

A

Abdomen of insects, structure, 42

Acanthidse, 147

Acarina, 25

Acrididse, 59

Adalia bipunctata, 177

Adult stage of insects, 47

Agallia sanguinolenta, 107

Alabama argillacea, 227

Aleyrodida^, 129

Alfalfa caterpillar, 243

weevil, 195
American silk worm, 240
Ametobolic, 48
Anasa tristis, 156
Anatomy of grasshopper, 39
Anopheles maculipennis, 249

punctipennis, 249, 250
Anosia plexippus, 245
Antenna, 38

Anthonomus grandis, 198
Ant lions, 169
Ants, 305

Apanteles glomeratus, 296, 297
Aphaniptera, 50
Aphanothrips striata, 90
Aphitlida%.117
Aphids, 117, 118
Aphis maidis, 123

maidi-radicis, 1 23
Aj)hrophora 4-notata, 104
Ai)idie, 310

Appendages of insects, head, 38
Apple aphis, 126

leaf hopper, 115

maggot, 287, 288
Apterygota, 48
Arachnida, 22
Aradida;, 314

Araneida, 24
Argas miniatus, 31

persicus, 31

refiexus, 30
Argentine ant, 307, 309
Armored scales, 134
Army worm, 227
Arphia sulphurea, 67
Arsenate of lead, 316
Arsenical bran mash, 317
Arthropoda, 17
Aspidiotus perniciosus, 137
Assassin bugs, 145
Athysanus exitiosus, 113
. obtutus, 106
Atropos, work of, 82

divinatoria, 83
Auchenorhynchi, 94

B

Bag-worm moths, 207
Balaninus obtusus, 198

proboscideus, 196, 197
Bark beetles, 203

hce, 130
Basilarchia archippus, 247
Beach locust, 65
Bed-bug, 147
Bee moth, 213
Bees, 310

and wasps, 291
Beetles, 172

Belostoma ameri(!ana, 144
Belostomidae, 142
Bembecida;, 310
Bembecina;, 308
Benacus griseus, 144
Bird lice, 83

(339)

340

INDEX

Bird tick, 28

Bittacus, 170

Black flies, 260

Blattidoe, 55

Blissus leucopterus, 151

Blood-sucking cone nose, 14.1

Blow fly, 277, 286

Blue-bottle fly, 285

Body structure, 38

Boll* weevil, 198

worm, 226
Book lice, 81
Boreus, 170
Bot flies, 267
Box elder bug, 156
BraconidiP, 296
Bran mash, arsenical, 317
Bristle tails, 48
Brown-tailed moth, 233
Bruchidai, 193
Buffalo gnats, 260

treehopper, 99
Bumble bee, 310
Buprestida% 181
Butterflies, 241
Bythoscopidic, 107

Cabbage butterfly, 242
Cacsesia roseana, 215
Caddice flies, 170
Calosoma calidum, 173

scrutator, 173, 174

sycophanta, 174
Camnula pellucida, 63
Campodea, 48
Canker worm, 225
Capsidte, 150
Carabidae, 173
Carpet beetles, 179

moth, 222
Carpocapsa pomonella, 215

saltitans, 218
Carrion beetles, 174
Cat flea, 290
Cattle louse, biting, 85

tick, 31
Cecropia moth, 240
Cerambycida?, 185
Cercopida', 104

Ceresa bubalus, 99
Ceuthophilus, 68
Chalcidida;, 296, 300.
Chalcis ovata, 300
Chestnut weevil, 196
Chiggers, 26
Chilopoda, 17
Chinch bug, 151
Chionaspis fm-furus, 136

salicis, 135, 136
Chion cinctus, 187, 188
Chu'onomidae, 253
Chrysobothris femorata, ISl
Cluysomelida;, 190
Chrysopa oculata, 167
Clary sopidae, 165
Cicada killer, 310
Cicadidse, 94
Cicadula 6-notata, 114
CicindeUdae, 173
Cimbex americana, 292
Cimex lectularius, 147, 148
Circulatory system of insects, 43
Classification of insects, 4s
Click beetles, 180
Clisiocampa americana, 235
Close wings, 214
Clothes moth, 222
Clothilla, 82
Clover-flower midge, 254

leafhopper, 107, 108

-leaf weevil, 195

-root borer, 205

-seed cateriDillar, 219
Clypeus, 40
Coccidffi, 130
Coccinse, 132
Coccinellidte, 175
Cockroaches, 55
Codling moth, 215
Coleoptera, 50, 172
Colias philodice, 245
CoUembola, 48, 54
Colorado potato beetle, 190
Conocephalus, 67
Conorrhinus sanguisugus, 146
Conotrachelus nenuphar, 196
Contact insecticides, 317
Control, insect, 315
Copris Carolina, 183
Coquillettia, 151

mimetica, 149, 151

INDEX

341

Coreidse, 155
Corisa harrisii, 141
Corisidse, 141
Corizus, 158

crassicornis, 158
Corn delphacid, 103

-leaf aphis, 123

-root aphis, 123

worm, 191
Cornicles, 118
Corrodentia, 49, 81
Corydalis cornuta, 165, 166
Cossidaj, 210
Cotton boll weevil, 198

worm, 227
Crambidffi, 214
Crambus, 214
Ctenocephalus canis, 290
Cucujidse, 177
Culex tseniorhynchus, 251
Culicidaj, 248
Cultural methods, 322
Cut worms, 229
Cyclorhapha, 266
Cynipidse, 295
CjTtophyllum concavum, 68

Dactylopiin.e, 131
Daddy-longlegs, 23
Damsel flies, 74
Danaidse, 245

Dasyneura leguminicola, 254
Datana, 224

ministra, 224
Delphacida?, 103
Deltocephalus inimicus, 111, 111
Dendroctonus, 205

valens, 203, 204
Dermacentor albipictus, 33

venusta, 32, 33
Dermanyssus avium, 28

gallinse, 29
Dermaptera, 49, 70
Dermestes lardarius, 178
Dermestid£B, 178
Destructive leaf hopper, 113
Devastating locust, 60
Diabrotica, 191

longicornis, 191, 192

1 Diabrotica 12-punctata, 192, 193

vittata, 191
Diapheromera femorata, 58
Diaspinse, 134
Dicranotropis maidis, 103
Digestive system of insects, 42
Dineutes americana, 174
Diplopoda, 18
Diptera, 50, 248
Direct methods for insect control,

315
Dissosteira Carolina, 66
Dog-day cicada, 98

flea, 290
Dorycephalus platyrhynchus, 110,

111
Draeculacephala mollipes, 109
Dragon flies, 74
Drosophila, 287
Dytiscidse, 174

E

Eakwigs, 49, 70

Economic entomology, 17, 302, 313
Ectobia germanica, 57
Eggs of insects, 45
Elaterida;, 180
Elm-leaf beetle, 192
Empoasca mali, 115
Endelomyia rosse, 293
Enemies, natural, of insects, 324
Engraver beetles, 203
Epeira scolopetaria, 24
Ephemerida, 49, 72
Ephestia kuehnieUa, 212
Eriocampoides limacina, 293
Euphorocera claripennis, 276
Euplexoptera, 70
Eurymus eurytheme, 243
Euthrips pyri, 89, 90
Euvanessa antiopa, 247
Exclusion and restriction nietliod of

insect control, 327
Eyes of insects, 39

Fall canker worm, 226
Field ants, 307 .

342

INDEX

Fire fly, 182
Flat-heacled borer, 181
Fleas, 289
Flesh flies, 286
Food habits of insects, 314
Forest flies, 288
Formicidse, 305
Formicina, 305
Fruit-tree bark beetle, 205
Fulgoridae, 101

Galerucella luteola, 194
Galleria mellonella, 213
Gall gnats, 253
Gamasidse, 28
Gastrophilus equi, 267, 268

hffimorrhoidalis, 270

nasalis, 270
Geometridse, 225
Giant water bug, 142
Gipsy moth, 232
Glassy-winged sharpshooter, 109
Glossary of terms, 329
Glossina morsitans, 283

palpalis, 283, 284
Gnats, 253

Grain aphis, spring, 123
Grape leaf hopper, 1 14

phylloxera, 129
Grapholitha interstinctana, 219
Grass thrips, 90
Green-bottle fly, 286

bug, 123
Ground beetles, 173
Gryllida;, 69

Gryilotalpa Columbia, 70
Gula, 40
Gyrinidffi, 174
Gyropus, 84

Hackberry-gall psyllids, 116
Hsematobia serrata, 279
Hsematopinus eurysternus, 161, 162

urius, 162
Handmaid moths, 224
Harlequin cabbage bug, 159
Harvestmen, 23

Harvest mites, 26
Hazel-nut weevil, 198
Head of insects, structure;, 38
Heliophila unipuncta, 228
Hellebore, 316
Hemiptera, 49, 93
Hesperidse, 241
Hessian fly, 255
Heterometabolic, 48
Heteroptera, 93, 140
Hexapoda, 38
Hickory borer, 187
Hippoboscidse, 288
Hippodamia convergens, 176
Hog louse. 162, 163
Holometabolic, 48
Homaloniyia brevis, 287
Homoptera, 93
Honey bee, 310

dew, 118

tubes, 118
Horn fly, 279
Hornet, 310,
Horse bot fly, 268

flies, 265

louse, biting, 86
House centipede, 17

fly, 277, 278
HvdnjbaticUp, 144
Hy(lr()i)hili(Ue, 174
Ilylastinus obscurus, 201, 205
Hymenoptera, 50, 291
Hyphantria cunea, 235
Hypoderma bovis, 271

lineata, 270

IcERYA purchasi, 132
Ichneumonidse, 295
Idiocerus alternatus, 108
Imago, 47

Indian meal moth, 211
Inimical leaf hopper, 111, 112
Insect control, 315

powder, 321
Insecticides, 315
Insects, relation, 312

structure, 38
Internal structure of insects, 42
Iridomvrmex humilis, 307

INDEX

343

Ischnoptera, 55

pennsylvanica, 55
Isoptera, 49, 70
Isosoma tritici, 301, 302
Itch mite, 30
Ixodidie, 30

Jassid^, 111
Jassoidea, 105
June bugs, 183

Katydid, 08

Kerosene as an insecticide, 319

Kissing bug, 145

Labia minor, 71, 72
Labium, 40
Labrum, 40
Lace bugs, 150
Lachnosterna, 183

fusca, 183, 184
Ladybird beetles, 175
Lampyridse, 182
Larder beetle, 178
Larval period, 47

stage, 40
Lead arsenate as an insecticide, 310
Leaf beetles, 190

bugs, 150

rollers, 215
Leafhopper terms, 100
Lebia grandis, 173
Legs of insects, structure, 41
Lepidocyrtus purpureus, 53
Lepidoptera, 50, 200
Lepisma, 48

domestica, 51, 53

saccharin a, 52, 54
Leptinotarsus decemlineatus, 190
Leptocoris trivittatus, 150, 157
Leptus americana, 27

irritans, 27
Leucania unipuncta, 227
Leucotermes flavipes, 70, 77, 81

Libellula pulchella, 75, 70

Lime-sulphur as an insecticide, 318

Limnogonus hesione, 145

Liotheidse, 84

Locustidse, 07

Locusts, 59

Locust-tree borer, 210

London purple as an insecticide,

310
Lucanidis, 182
Lucanus dama, 182
Lucilia csesar, 285
Luna moth, 240
Lyctidse, 178

Lyctus planicollis, 178, 179
Lygseida;, 151
Lysiphlebus, 123

tritici, 290, 298

M

Machinery for the application of

insecticides, 322
Macrodactylus subspinosus, 184
Macrosiphum pisi, 121, 122
Mallophaga, 49, 83
Mandibles of insects, 40
Mantida?, 57
Mantispidaj, 105
Maple scale, 133
Margaropus annulatus, 31
Masked bed-bug hunter, 140
Mating of insects, 45
Maxilla of insects, 40
May beetles, 183

fhes, 72
Mayetiola destructor, 255, 250
Meat fly, 280
Mecoptera, 50, 109
Mediterranean flour moth, 212
Megilla maculata, 170
Melanoplus atlanis, 02, 05

femur-rubrum, 01, 62

spretus, 00
Melanotus communis, 180
Mellitia satyriniformis, 223
Melophagus ovinus, 288
Membracida?, 98
Menojjon pallidum, 84
Mentum of insects, 40
Metamorphosis of insects, 47

344

INDEX

Micropylc, 45

Mole cricket, 70

Monarch butterfly, 245

Monoinera blatchleyi, 59

Mosquitoes, 248

Mouth structure of insects, 40

Mullein thrips, 92

nigra, 92
Murgantia histrionica, 159
Musca domestica, 277, 278
Muscidae, 277
Muscina stabulans, 283
Museum beetle, 179
Myriopods, 17
Myrmeleonidse, 169

N

Nabid^, 147

Natural enemies of insects, 324

Necrophorus, 175

Nectaries, 118

Nepidse, 142

Nervous system of insects, 43

Neuroptera, 49, 165

Noctuidse, 226

Notolophus leucostigma, 230

Notonecta irrorata, 141

undulata, 141, 142
Notonectida;, 142
Nut weevils, 198
Nymphalidse, 247

Ocelli, 39
Odonata, 49, 74
(Ecanthus, 69

fasciatus, 69

niveus, 69
(Estridse, 267
CEstrus ovis, 275
Oncometopia undata, 109
Onion thrips, 90
Onycophora, 17
Ophion, 296
Orange dog, 242

white fly, 130
Oriental cockroach, 56
Ormenis pruinosa, 101

Orthezia solidaginis, 131, 132
Ortheziinae, 131
Orthoptera, 48, 54
Orthorapha, 248
Otioceras, 102
Owlet moths, 226
Ox bot fly, 270
Oyster-shell scale, 136

Pachypsylla celtidis-mamma, 116

Paleacrita vernata, 225

Palpus, 40

Panorpidse, 169

Papilio cresphontes, 242

PapiHonidse, 241

Paraglossa, 40

Parasita, 94, 160

Parasitica, 295

Parasitic insects, 324 _

Paris green as insecticide, 315

Parthenogenesis in aphids, 118

Passalus cornutus, 182

Pea aphis, 121, 122

weevil, 193
Peach-tree borer, 222
Pear slug, 293

thrips, 90

-tree psylla, 115, 116
Pedipalpi, 23
Pentatomidse, 159
Periplaneta orientalis, 56
Perla, 49

1 Persian insect powder, 321
! Phalangida, 23
Phasmidse, 58
Phasmomantis Carolina, 57
i Philopteridae, 84
Phlegethontius 5-maculata, 206
Phloeothrips verbasci, 92
j Phormia terrsenova, 284
Phorodon humuli, 119
Phylloxera, grape, 129
Phymatidse, 147
Phytonomus punctatus, 195
Pierida3, 242
Pieris rapse, 242
Pigeon tick, 30
I Pilophorus, 151
' Pimpla, 296

INDEX

345

Pimpla conquisitor, 295, 297
Pissodes strobi, 200
Plant lice, 117
Platypsyllidse, 174
Plecoptera, 49, 72
Plodia interpunctella, 211
Plum curculio, 196
Podisus maculiventris, 159
Podura, 48

Porthetria dispar, 232
Praying mantis, 57
Predaceous bugs, 145

insects, 324
Principles of economic entomology,

312
Prionoxystus robinia^ 210
Prionus, 185
Proctotrupidse, 296, 305
Proventriculus, 42
Pseudococcus citri, 131
Pseudoscorpionida, 23
Pseudova, 118
Psocidse, 81
Psoroptes communis, 34

var ovis, 35
PsyllidEe, 115

Pteromalus puparum, 300, 301
Pterygota, 48, 54
Pulvinaria innumeral)ilis, 132, 133
Pupa stage of insects, 47
Pyralida;, 211
Pyralis farinalis, 211
Pyrethrum as an insecticide, 321

Ranatra americana, 143
Red spider, 25
Reduviidae, 145
Reduvius personatus, 146
Relation of insects, 312
Reproduction of insects, 44
Reproductive organs of insects,

44
Respiratory system of insects, 43
Restriction as a method of insect

control, 327
Rhagoletis pomonella, 287, 288
Rhyncophora, 195
Rocky Mt. locust, 60
Rose chafer, 184

Rose slug, 293
Round-headed borer, 187
Rove beetles, 175

San Jose scale, 137
Sanninoidea exitiosa, 222, 223
Saperda Candida, 187, 189
Sarcophagidse, 286
Sarcoptes scabiei, 36
Sarcoptida;, 35
Saw-toothed beetle, 177, 178
Scale insects, 130
Scarabseidse, 182
Schizoneura americana, 123

lanigera, 126
Scolytidse, 203
Scolytus rugulosus, 202, 205
Scorpionida, 22
Scorpion flies, 169
Scorpions, 22
Screw-worm fly, 277
Scutigera forceps, 20, 21
Sericophanes, 151

ocellatus, 150
Sesiidse, 222

Seventeen-year cicada, 95
Sharpshooter, 109
Sheep bot fly, 275

scab mite, 35

tick, 288
Short-nosed ox louse, 161
Shovel-nosed leaf hopper, 110, HI
Sialidse, 165
Silk worm, 240
Silpha, 175
Silphida;, 175
Silvertop, 90
SimuliidiB, 260
Simulium pecuarum, 261
Siphocoryne avense, 119
Siphonaptera, 50, 289
Six-spotted leaf hopper, 114
Skippers, 241
Smynthurus, 48
Snowy tree cricket, 69
Social wasps, 310
Sod worm, 214
Solpugida, 23
Southern buffalo gnat, 261

346

INDEX

Special senses of insects, 44
Sphecina, 308
Sphecius s])eciosus, 310
Spined soldier bug, 159
Spiracles, 42
Spotted-fever tick, 32
Spraying codling moth, 216
Spring grain aphis, 123
Spring tails, 48
Squash beetle, 191

bug, 155

-vine borer, 222
Stable fly, 282
Stag beetle, 182
StaphylinidcC, 175
Stegomyia fasciata, 252
Sternorhynchi, 94, 115
Stink bugs, 159
Stomoxys calcitrans, 282
Stone crickets, 68

flies, 72
Structure of insects, 38
Submentum, 40
Sugar-cane hopper, 103
Swallowtail butterflies, 241
Sword bearers, 67
Sylvanus surinamensis, 177
SyrphidiB, 266

Tabanid.e, 265
Tabanus atratus, 266
Tachinidffi, 275
Tarnished plant bug, 150.
Tenderfoot leafhopper, 109
Tent caterpillar, 235
Tenthredinida>, 292
Terebrantia, 88
Termites, 76
Termitida;, 76
Tetranychus bimaculatus, 25

gloveri, 26
Tettigoniellida>, 108
Thalessa, 296

atrata, 295

lunator, 295
Thorax structure of insects, 41
Thread-legged bug, 147
Thripida^, 88
Thrips taVjaci, 90

Thrips tritici, 89

Thyridopteryx ephemcMU-fonnis,

207, 209
Thysanoptera, 49, 87
Thysanura, 48, 52
Tibicen septendecim, 94, 95
Tick, cattle, 31

spotted fever, 31
Ticks, 30
Tiger beetles, 173
Tinea pellionella, 221
Tineidaj, 221
Tineola biselliella, 222
Tingitida;, 150
Tobacco extract, 320
Tomato-worm larva, 206
Tortricidaj, 215

Toxoptera graminum, 122, 123
Trachea of insects, 43
Transformations of insects, 45
Tree crickets, 69

-hoppers, 98
Tremex columba, 294
Trichodectes, 84

parumpilosus, 86

scalaris, 85
Trichoptera, 50, 170
Trimerotropis maritima, 64, 65
Trombidiidse, 26
Tsetse flies, 283
Tussock moths, 230
Typhlocyba comes, 114
Typhlocybida;, 114

Unity of habit of insect groups, 314
Uroceridse, 293

Vedalia, 177
cardinalis, 132

Vespa germanica, 310
maculata, 310

Vespidffi, 310

Viceroy butterfly, 247

INDEX

347

W

Walking-stick, 58
Wasps, 308
Water beetles, 174

boatmen, 141

bugs, 142

scorpions, 142

striders, 144
Web-worm moths, 234
Wheel bug, 146
Whip scorpion, 23
Whirligig beetles, 174
White ants, 76

fly, 130

-marked tussock moth, 230

pine weevU, 200, 203

Willow saw fly, 292

scale, 135
Wings, structure of insects', 41
Wire worm, 180
Wood borers, 185
Woolly aphis, 126

Yellow-fever mosquito, 25"j
Yellow jacket, 310

Zaitha fluminea, 141

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