{Homoptera.
4. Hemiptera {Hemiptera IX. {Heteroptera.
{Thysanoptera VIII.
5. Diptera {Diptera XVI. {Including Aphaniptera or Siphonaptera
{of some authors.
6. Orthoptera {Orthoptera VII.
{Dermaptera VI.
{Trichoptera XIII }
{Mecoptera XII }Neuroptera.
{Neuroptera XI }
7. Neuroptera {Platyptera V }
{Plecoptera IV }
{Odonata III }Pseudo-neuroptera.
{Ephemeroptera II }
{Thysanura I }
It will be seen that the changes are not so great as would at first
appear. The three more important orders, namely, the Hymenoptera,
Coleoptera, and Lepidoptera, remain substantially the same in all
classifications, and so with the three orders next in importance--the
Hemiptera, Diptera, and Orthoptera. All that has been done with these
three has been to rank as separate orders what by former authors were
preferably considered as either families or suborders. The principal
change is in the Neuroptera, of which no less than eight orders have
been made. This is not to be wondered at, because the order, as formerly
construed, was conceded to be that which represents the lowest forms
and more synthetic types of insects, and as such necessarily contained
forms which it is difficult to classify definitely.
[Illustration: FIG. 3.--Cross section of Fig. 2.]
In the discussion of the characteristics, habits, number of species, and
importance of the several groups, I follow, with such changes as the
advances in the science of entomology have made necessary, the
arrangement shown in Fig. 1.
"Order HYMENOPTERA ([Greek: ymen], a membrane; [Greek: pteron], wing).
Clear or Membrane-winged Flies: Bees, Wasps, Ants, Saw-flies, etc.
Characterized by having four membranous wings with comparatively few
veins, the hind part smallest. The transformations are complete: _i.
e._, the larva bears no resemblance to the perfect insect.
[Illustration: FIG. 4.--Bold-faced Hornet, _Vespa maculata_. (After
Sanborn).]
"Some of the insects of this order are highly specialized, and their
mouth-parts are fitted both for biting and sucking, and in this respect
they connect the mandibulate and haustellate insects. The common
Honey-bee has this complex structure of the mouth, and if the editors of
our agricultural papers would bear the fact in mind, we should have less
of the never-ending discussion as to whether bees are capable of
injuring fruit at first hand. The lower lip (_labium_) is modified into
a long tongue, sheathed by the lower jaws (_maxillae_), and they can sip,
or, more properly speaking, lap up nectar; while the upper jaws
(_mandibulae_), though not generally used for purposes of manducation,
are fitted for biting and cutting. The Hymenoptera are terrestrial,
there existing only a very few degraded, swimming forms.
[Illustration: FIG. 5.--An Ichneumon Parasite, _Pimpla annulipes_,
showing male and female abdomen.]
[Illustration: FIG. 6.--A Chalcid Parasite, _Chalcis flavipes_.]
"This order is very naturally divided into two sections--the ACULEATA
and TEREBRANTIA. The aculeate Hymenoptera, or Stingers, comprise all the
families in which the abdomen in the female is armed with a sting
connected with a poison reservoir, and may be considered the typical
form of the order, including all the social and fossorial species. The
insects of this section must be considered essentially beneficial to
man, notwithstanding the occasional sting of a bee or wasp, the boring
of a carpenter bee, or the importunities of the omnipresent ant. Not
only do they furnish us with honey and wax, but they play so important a
part in the destruction of insects injurious to vegetation that they may
be looked upon as God-appointed guards over the vegetal
kingdom--carrying the pollen from plant to plant, and insuring the
fertilization of di[oe]cious species, and the cross-fertilization of
others; and being ever ready to clear them of herbivorous worms which
gnaw and destroy. The whole section is well characterized by the
uniformly maggot-like nature of the larva. The transformations are
complete, but the chitinous larval covering is often so very thin and
delicate that the budding of the members, or gradual growth of the pupa
underneath, is quite plainly visible, and the skin often peels off in
delicate flakes, so that the transition from larva to pupa is not so
marked and sudden as in those insects which have thicker skins.
[Illustration: FIG. 7.--A Horn-tail, _Tremex columba_. _a_, larva,
showing Thalessa larva attached to its side; _b_, head of larva, front
view, enlarged; _c_, female pupa, ventral view; _d_, male pupa, ventral
view; _e_, adult female--all slightly enlarged.]
"The terebrantine Hymenoptera, or Piercers, are again divisible into two
subsections: first, the ENTOMOPHAGA, which are, likewise, with the
exception of a few gall-makers, beneficial to man, and include the
parasitic families, and the gall-flies; second, the PHYTOPHAGA,
comprising the Horn-tails (_Uroceridae_), and the Saw-flies
(_Tenthredinidae_), all of which are vegetable feeders in the larval
state, those of the first family boring into trees, and those of the
second either feeding externally on leaves or inclosed in galls. They
are at once distinguished from the other Hymenoptera by the larvae
having true legs, which, however, in the case of the Horntails, are very
small and exarticulate. The larvae of many Saw-flies have, besides,
prolegs, which are, however, always distinguishable from those of
Lepidopterous larvae by being more numerous and by having no hooks.
[Illustration: FIG. 8.--Saw-fly and Larva. _Pristiphora grossulariae_;
_a_, larva; _b_, imago, Walsh.]
"Order COLEOPTERA ([Greek: koleos], a sheath; [Greek: pteron], wing).
Beetles or Shield-winged Insects. Characterized by having four wings,
the front pair (called _elytra_) horny or leathery, and usually united
down the back with a straight suture when at rest, the hind ones
membranous and folded up under the elytra when at rest. Transformations
complete.
[Illustration: FIG. 9.--A Chafer, _Cotalpa lanigera_. (After Packard.)]
[Illustration: FIG. 10.--A Longicorn, _Saperda candida_. _a_, larva;
_b_, pupa; _c_, beetle.]
"This is an order of great importance, and in the vast number and
diversity of the species comprised in it outranks any of the others. The
ease with which the insects of this order are obtained and preserved
make it one of the most attractive to the amateur, and beetles are,
perhaps, of all insects, the best known and understood in the popular
mind. For the same reason they have, in the perfect state, received most
attention from the entomologists, but their transformations and
preparatory forms yet offer a wide and inviting field for the student.
The simplest and best-known classification of the beetles is the tarsal
system, founded on the number of joints to the tarsi, by which we get
four great sections: (1) PENTAMERA, in which all the tarsi are
5-jointed; (2) HETEROMERA, with the four anterior 5-jointed and the two
posterior 4-jointed; (3) PSEUDO-TETRAMERA, with apparently only four
joints to all the tarsi, though, in reality, there is a fifth
penultimate joint, diminutive and concealed; (4) PSEUDO-TRIMERA, with
apparently only three joints to all the tarsi. This system, like most
others, is not perfect, as there are numerous species not possessing
five joints to the tarsi belonging to the first section; and for
practical purposes beetles may be very well arranged according to habit.
We thus get, first, the ADEPHAGA, or carnivorous species, including all
those which prey on other living insects, and to which, following Mr.
Walsh, I have, for obvious reasons, applied the suggestive term
'Cannibal'; second, the NECROPHAGA, comprising those which feed on
carrion, dung, fungi, and decaying vegetation; third, the PHYTOPHAGA,
embracing all those feeding on living vegetation. This arrangement is by
no means perfect, for there are beetles which are carnivorous in the
larva and herbivorous in the imago state; while some of the NECROPHAGA
are actually parasitic. Yet, it is not more artificial than others which
have been proposed. The carnivorous species, broadly speaking, are
_Pentamerous_, the only striking exception being the Coccinellidae
(Lady-birds), which are _Pseudo-trimerous_. The carrion-feeders are also
_Pentamerous_; but vegetable-feeders are found in all the tarsal
divisions, though the _Pseudo-tetramera_ are the more essentially
herbivorous, and consequently the most injurious."
[Illustration: FIG. 11.--The Plum Curculio, _Conotrachelus nenuphar_.
_a_, larva; _b_, pupa; _c_, beetle; _d_, plum showing egg-puncture and
crescent.]
[Illustration: FIG. 12.--A Soldier-beetle, _Chauliognathus
pennsylvanicus_. _a_, larva; _b-h_, parts of larva enlarged; _i_,
beetle.]
[Illustration: FIG. 13.--The Bogus Potato-beetle, _Doryphora juncta_.
_a_, eggs; _b_, larvae; _c_, beetle; _d_ and _e_, parts of beetle
enlarged.]
"Order LEPIDOPTERA ([Greek: lepis], a scale; [Greek: pteron], wing).
Butterflies and Moths, or scaly-winged insects. Characterized by having
four branching-veined membranous wings, each more or less densely
covered on both sides with minute imbricated scales which are attached
by a stalk, but which easily rub off, and appear to the unaided eye like
minute particles of glistening dust or powder. Transformations complete.
[Illustration: FIG. 14.--A Butterfly, _Pieris oleracea_.]
"Next to the Lepidoptera, the Coleoptera are, perhaps, most familiar to
the popular mind. Every one admires the beauty of these frail creatures,
dressed in every conceivable pattern, and adorned with every conceivable
color, so as to rival the delicate hues of the rainbow, and eclipse the
most fantastic and elaborate designs of man. When magnified, the scales,
to which this beauty of pattern and color is entirely due, present all
manner of shapes, according to the particular species or the particular
part of the individual from which they are taken. According to
Lewenhoeck, there are 400,000 of these scales on the wing of the common
silkworm.
[Illustration: FIG. 15.--A Sphingid, _Ampelophaga myron_.]
"The transformations of these insects are complete, and the changes are
usually so sudden and striking as to have excited the wonder and
admiration of observers from earliest times.
"The more common form of the larva is exampled in the ordinary
caterpillar--a cylindrical worm with a head, twelve joints and a
sub-joint; six thoracic or true legs, four abdominal and two anal
prolegs. But there is a great variety of these larvae, some having no
legs whatever, some having only the jointed legs, and others having
either four, six, eight, or ten, but never more than ten prolegs. With
few exceptions they are all vegetable-feeders, and with still fewer
exceptions, terrestrial. The perfect insects make free use of their
ample wings, but walk little; and their legs are weak, and not modified
in the various ways so noticeable in other orders, while the front pair
in some butterflies are impotent.
[Illustration: FIG. 16.--A Moth, _Utetheisa bella_.]
"As an order this must be considered the most injurious of the seven.
"A convenient system of classification for the Lepidoptera is based on
the structure of the antennae. By it we get two great sections: 1st,
Butterflies (RHOPALOCERA); 2d, Moths (HETEROCERA), which latter may
again be divided into Crepuscular and Nocturnal Moths. Butterflies are
at once distinguished from moths by their antennae being straight, stiff
and _knobbed_, and by being day-fliers or diurnal; while moths have the
antennae tapering to a point, and are, for the most part, night-flyers or
nocturnal. The crepuscular moths, composed mostly of the Sphinges or
Hawk-moths, hover over flowers at eve, and connect the two sections not
only in habit, but in the character of the antennae which first thicken
toward the end, and then suddenly terminate in a point or hook.
[Illustration: FIG. 17.--A Clothes-moth (_Tinea pellionella_)--enlarged.
_a_, adult; _b_, larva; _c_, larva in case.]
"Order HEMIPTERA ([Greek: hemi], half; [Greek: pteron], wing), Bugs. The
insects of this order are naturally separated into two great sections;
1st, Half-winged Bugs, or HETEROPTERA ([Greek: heteros], different;
[Greek: pteron], wing) having the basal half of the front wings (called
_hemelytra_) coriaceous or leathery, while the apical part is
membranous. The wings cross flatly over the back when at rest; 2d,
Whole-winged Bugs, or HOMOPTERA ([Greek: homos], equal; [Greek: pteron],
wing), having all four wings of a uniform membranous nature and folding
straight down the back when at rest. The latter, if separated, may be
looked upon as a Suborder.
[Illustration: FIG. 18.--A Plant-bug (_Euschistus punctipes_).]
"Transformations incomplete; _i. e._, the larvae and pupae have more or
less the image of the perfect insect, and differ little from it except
in lacking wings.
[Illustration: FIG. 19.--A Soldier-bug (_Milyas cinctus_). _b_, beak
enlarged.]
"The genuine or half-winged Bugs (Figs. 18 and 19) are usually flattened
in form, when mature; though more rounded in the adolescent stages. They
may be divided into Land Bugs (_Aurocorisa_) and Water Bugs
(_Hydrocorisa_). The species of the first division very generally
possess the power of emitting, when disturbed or alarmed, a nauseous,
bed-buggy odor, which comes from a fluid secreted from two pores,
situated on the under side of the metathorax. Such well-known insects as
the Bed-bug and Chinch-bug belong here. The habits of the species are
varied, and while some are beneficial, others are quite injurious to
man.
[Illustration: FIG. 20.--A Tree-hopper (_Ceresa bubalus_). _a_, side;
_b_, top view.]
"The Whole-winged Bugs (Figs. 20 and 21), on the contrary, are all
plant-feeders, and with the exception of a few, such as the Cochineal
and Lac insects, are injurious. The secretion of a white, or bluish,
waxy, or farinose substance from the surface of the body is as
characteristic of this section as the nauseous odor is of the first. It
forms three natural divisions, arranged according to the number of
joints to the tarsi--namely TRIMERA, with three joints; DIMERA, with two
joints; and MONOMERA, with one joint to the tarsi."
Suborder THYSANOPTERA ([Greek: thysanos], a fringe; [Greek: pteron],
wing): This suborder contains the single family _Thripidae_, which
comprises minute insects commonly known as Thrips, and of which a common
species, _Thrips striatus_, is shown in the accompanying figure. (See
Fig. 22.) They bear strong relations to both the Pseudoneuroptera and
the Hemiptera and by later writers are generally associated with the
latter order. They feed on plants, puncturing and killing the leaves, or
on other plant-feeding species of their own class, and are characterized
by having narrow wings crossed on the back when at rest, and beautifully
fringed, from which latter feature the name of the suborder is derived.
[Illustration: FIG. 21.--A Plant-louse (_Schizoneura lanigera_). _a_,
infested root; _b_, larva; _c_, winged insect; _d-g_, parts of perfect
insect enlarged.]
The mouth parts are peculiar in that they are intermediate in form
between the sucking beak of Hemiptera and the biting mouth parts of
other insects.
[Illustration: FIG. 22.--_Thrips striatus_, with wings enlarged at
side.]
Their eggs resemble those of Hemiptera; the larvae and pupae are active,
and in form resemble the adult, except in the absence of wings. Some
species, also, are wingless in the adult stage.
The pupae are somewhat sluggish and the limbs and wings are enclosed in a
thin membrane which is expanded about the feet into bulbous
enlargements, giving rise to the name "bladder-footed" (Physopoda)
applied to these insects by Burmeister.
"Order DIPTERA ([Greek: dis], twice; [Greek: pteron], wing) or
Two-winged Flies. The only order having but two wings, the hind pair
replaced by a pair of small, slender filaments clubbed at tip, and
called halteres, poisers, or balancers.
[Illustration: FIG. 23.--A Mosquito (_Culex pipiens_). _a_, adult; _b_,
head of same enlarged; _e_, portion of antenna of same; _f_, larva; _g_,
pupa. (After Westwood.)]
[Illustration: FIG. 24.--A Hawk-fly (_Erax bastardi_). _a_, perfect
insect; _b_, pupa; larva shown at side.]
[Illustration: FIG. 25.--A Flesh-fly (_Sarcophaga carnaria_, var.
_saracenae_). _a_, larva; _b_, puparium; _c_, adult insect with enlarged
parts.]
"No order surpasses this in the number of species or in the immense
swarms of individuals belonging to the same species which are frequently
met with. The wings, which are variously veined, though appearing naked
to the unaided eye, are often thickly covered with very minute hairs or
hooks. As an order the Diptera are decidedly injurious to man, whether
we consider the annoyances to ourselves or our animals of the Mosquito,
Buffalo-gnat, Gad-fly, Breeze-fly, Zimb or Stomoxys, or the injury to
our crops of the Hessian-fly, Wheat-midge, Cabbage-maggot, Onion-maggot,
etc. There are, in fact, but two families, Syrphidae and Tachinidae, which
can be looked upon as beneficial to the cultivator, though many act the
part of scavengers. No insects, not even the Lepidoptera, furnish such a
variety of curious larval characters, and none, perhaps, offer a wider
or more interesting field of investigation to the biologist. It is
difficult to give any very satisfactory arrangement of these Two-winged
flies, though they easily fall into two rather artificial sections.
These are: 1st, NEMOCERA, or those with long antennae, having more than
six joints, and palpi having four or five joints. The pupa is naked, as
in the Lepidoptera, with the limbs exposed. This kind of pupa is called
_obtected_. 2d, BRACHOCERA, or those with short antennae, not having more
than three distinct joints, and palpi with one or two joints. The pupa
is mostly _coarctate_, _i. e._, is formed within, and more or less
completely connected with, the hardened and shrunken skin of the larva.
[Illustration: FIG. 26.--The Sheep Bot (_[OE]strus ovis_). 1, 2, flies;
3, puparium; 4, 5, and 6, larvae or bots.]
"The most anomalous of the Diptera are the Forest-flies and Sheep-ticks
(_Hippoboscidae_). They have a horny and flattened body, and resemble
lice in their parasitic habits, living beneath the hair of bats and
birds. Their mode of development has always attracted the attention of
entomologists. The larvae are hatched in the abdomen of the female, which
is capable of distention. There it remains and, after assuming the pupa
state, is deposited in the form of a short, white, egg-like object,
without trace of articulation, and nearly as large as the abdomen of the
female fly. Closely allied to these are the Bat-ticks (_Nycteribidae_),
which possess neither wings nor balancers, and remind one strongly of
spiders.
"In this order we may also place certain wingless lice (such as _Braula
c[oe]ca_, Nitzch), which infests the Honey-bee in Europe, northern
Africa, and western Asia, but which has not yet been detected in this
country.
[Illustration: FIG. 27.--A Flea (_Pulex_). (From Packard.)]
"Suborder APHANIPTERA ([Greek: aphanes], inconspicuous; [Greek: pteron],
wing) or Fleas, comprising the single family Pulicidae, now placed with
the Diptera. Everybody is supposed to be familiar with the appearance of
the Flea--its bloodthirsty propensities and amazing muscular power; and
while everyone may not have the leisure and means to experience the
exhilarating influence of the chase after larger animals, there is no
one--be he never so humble--who may not indulge in the hunt after this
smaller game! In place of wings the flea has four small, scaly plates.
The minute eggs--about a dozen to each female--are laid in obscure
places, such as the cracks of a floor, the hair of rugs, etc., and the
larva is worm-like and feeds upon whatever animal matter--as grease and
blood--or decaying vegetable matter it can find.
"Order ORTHOPTERA ([Greek: orthos], straight; [Greek: pteron], wing), or
Straight-winged Insects. Characterized by having the front wings (called
_tegmina_) straight and usually narrow, pergameneous or parchment-like,
thickly veined, and overlapping at tips when closed; the hind wings
large and folding longitudinally like a fan. Transformations incomplete.
[Illustration: FIG. 28.--A Locust (_Acridium americanum_).]
[Illustration: FIG. 29.--A Tree-cricket (_Orocharis saltator_). _a_,
female; _b_, male.]
[Illustration: FIG. 30.--The Croton Bug or German Cockroach
(_Phyllodromia germanica_). _a_, first stage; _b_, second stage; _c_,
third stage; _d_, fourth stage; _e_, adult; _f_, adult female with
egg-case; _g_, egg-case--enlarged; _h_, adult with wings spread--all
natural size except _g_.]
"The insects of this order have a lengthened body and very robust jaws,
with a correspondingly large head. The legs are strong, and fashioned
either for grasping, running, climbing, jumping, or burrowing. As in the
other orders, where the transformations are incomplete, the young differ
little from the parent, except in the want of wings; and in many
instances even this difference does not exist, as there are numerous
species which never acquire wings. There are no aquatic Orthoptera. Some
are omnivorous, others carnivorous, but most of them herbivorous. They
form four distinct sections: 1st, CURSORIA, Cockroaches; 2d, RAPTATORIA,
Mantes; 3d, AMBULATORIA, Walking-sticks; 4th, SALTATORIA, Crickets,
Grasshoppers, and Locusts.
[Illustration: FIG. 31.--Hind wing of Earwig. (From Comstock.)]
[Illustration: FIG. 32.--An Earwig. (From Packard.)]
"Suborder DERMAPTERA[2] ([Greek: derma], skin; [Greek: pteron], wing),
or Earwigs, consisting of the single family Forficulidae, which may be
placed with the Orthoptera. They are rare insects with us, but very
common in Europe, where there prevails a superstition that they get into
the ear and cause all sorts of trouble. The front wings are small and
leathery; the hind ones have the form of a quadrant, and look like a fan
when opened; and the characteristic feature is a pair of forceps-like
appendages at the end of the body, best developed in the males. They are
nocturnal in habit, hiding during the day in any available recess. The
female lays her eggs in the ground, and singularly enough, broods over
them and over her young, the latter crowding under her like chicks under
a hen."
[2] Euplexoptera of some authors from [Greek: eu], well;
[Greek: plecho], folded, referring to the folded wings.
[Illustration: FIG. 33.--A Dragon-fly (_Libellula trimaculata_). (From
Packard.)]
"Order NEUROPTERA ([Greek: neuron], nerve; [Greek: pteron], wing), or
Nerve-winged insects. Characterized by having the wings reticulate with
numerous veins so as to look like net-work. The order forms two natural
divisions, the first including all those which undergo a complete, and
the second, called Pseudo-neuroptera (Dictyotoptera, Burmeister),
those which undergo an incomplete metamorphosis. * * * The insects of
this order are, as a whole, more lowly organized, and more generally
aquatic, than either of the others. A natural arrangement of them is
difficult on account of their degradational character. They present
forms which are synthetic and closely approach the other orders, and the
evolutionist naturally looks upon them as furnishing an idea of what the
archetypal forms of our present insects may have been. They are, as a
rule, large and sluggish, with the body parts soft and little
specialized, and the muscles weak. Their remains are found in the
Devonian and Carboniferous deposits.
"They are mostly carnivorous, and with the exception of the White-ants
and certain Book-lice they none of them affect man injuriously, while
some are quite beneficial."
[Illustration: FIG. 34.--Caddis-fly, larva and its case. (From
Packard.)]
The first division of this order, or the Neuroptera proper,
characterized by having incomplete metamorphoses, may be considered
under the three following suborders:
"Suborder TRICHOPTERA ([Greek: thrix], hair; [Greek: pteron], wing), or
Caddis-flies, containing the single family Phryganeidae, and placed with
the Neuroptera, though bearing great affinities with the Lepidoptera.
Every good disciple of Walton and lover of the "gentle art" knows the
value of the Caddis-fly, or Water-moth, as bait. These flies very much
resemble certain small moths, the scales on the wings of the latter
being replaced in the former with simple hairs. The larvae live in the
water and inhabit silken cases, which are usually cylindrical and
covered with various substances, according to the species, or the
material most conveniently obtained by the individual."
Suborder MECOPTERA ([Greek: mekos], length; [Greek: pteron], wing). This
suborder includes a peculiar group of insects, the most striking
characteristics of which are the mouth-parts, which are prolonged into a
rostrum or beak. The wings are long and narrow, and of nearly equal
size. The abdomen of the male is constricted near its posterior end and
terminates in long clasping organs from which these insects obtain the
common name of Scorpion-flies.
[Illustration: FIG. 35.--Panorpa or Scorpion-fly. (From Packard.)]
The larvae of one genus (_Panorpa_) are remarkable for their great
resemblance to the larvae of Lepidoptera. They have, however, eight pairs
of abdominal legs. The habits of these insects are not well known, but
they are supposed to be generally.
Suborder NEUROPTERA. This group as restricted by modern authors is a
small one, including the largest species, as in the Hellgrammite, the
Lace-wing Flies, the Ant-lions, and the Mantispas representing the
families, Sialidae and Hemerobiidae, with their subfamilies. The first
includes the so-called Hellgrammite Fly (_Corydalus cornutus_), one of
our largest and most striking insects, the larvae of which is known as
Dobsons by anglers, and is aquatic and carnivorous in habit. The
Hemerobiidae is a large family, comprising, as a rule, delicate insects
with rather ample gauzy wings. The larvae are predaceous. The common
Lace-wing flies are among our most beneficial insects, destroying
plant-lice and other soft-bodied species. To the same family belongs the
Ant-lion (_Myrmeleon_), the larvae of which have the curious habit of
constructing a funnel-shaped burrow in the sand, in the bottom of which
they conceal themselves and wait for any soft-bodied insects which may
fall into the trap. This family also includes the peculiar Mantis-like
insects belonging to the genus _Mantispa_. As in the true Mantis, the
prothorax of these insects is greatly elongated and the first pair of
legs are fitted for grasping. The larvae are parasitic in the egg-sacs of
certain large spiders (genera _Licosa_, _Dolomedes_, etc.), and undergo
a remarkable change in form after the first molt. In the first stage the
larvae are very agile, with slender bodies and long legs. After molting
the body becomes much swollen and the legs are much shortened, as are
also the antennae, the head becoming small and the general appearance
reminding one of the larva of a bee.
[Illustration: FIG. 36.--Lace-wing fly. _a_, eggs, _b_, larva, _c_,
cocoons, _d_, fly with left wings removed.]
[Illustration: FIG. 37.--An Ant-lion (_Myrmeleon_). (From Packard.)]
[Illustration: FIG. 38.--Myrmeleon larva.]
[Illustration: FIG. 39.--_Mantispa_ with side view beneath. (From
Packard.)]
The second section of the Neuroptera, characterized by complete
metamorphosis, comprises the following suborders:
Suborder PLATYPTERA ([Greek: platys], flat; [Greek: pteron], wing).
Under this head are grouped the White-ants (_Termitidae_), the Bird-lice
(_Mallophaga_), and the Book-mites (_Psocidae_). The suborder receives
its name from the fact that in the case of the winged forms the wings,
when at rest, are usually laid flat upon the back of the insect. The
Mallophaga, or Bird-lice, are degraded wingless insects, and are
parasitic chiefly on birds, but also on mammals. In shape of body and
character of the mouth-parts they are most nearly allied to the Psocidae.
The latter family includes both winged and wingless forms, the
Book-mites belonging to the latter category. The winged forms may be
illustrated by the common species, _Psocus venosus_ (see Fig. 40). The
legs and antennae are long and slender and the wings are folded roof-like
over the body when the insect is at rest. They feed on lichens and dry
vegetation.
The Termitidae are represented in this country by the White-ant (_Termes
flavipes_), which is frequently so destructive to woodwork, books, etc.
The term White-ant applied to these insects is unfortunate, as in
structure they are widely separated from ants and resemble them only in
general appearance and also in their social habits. Like the ants they
live in colonies and have a number of distinct forms, as winged and
wingless, males and females, and workers and soldiers.
[Illustration: FIG. 40.--_Psocus venosus._ (From Comstock.)]
Suborder PLECOPTERA ([Greek: plektos], plaited; [Greek: pteron], wing).
Closely allied to the latter suborder is the suborder Plecoptera, which
includes the single family Perlidae or Stone-flies. The larvae and pupae of
these insects are aquatic, being often found under stones in water,
whence the name. The adults are long, flattened insects, with long
antennae. The wings are ample and are somewhat folded or plaited, from
which character the suborder takes its name.
[Illustration: FIG. 41.--A Stone-fly (_Pteronarcys regalis_). (From
Comstock.)]
Suborder ODONATA ([Greek: othous], tooth). This includes
the Dragon-flies or Libellulidae, the most common and the best known of
the Neuroptera. The larva and the active pupa or nymph are aquatic and
are predaceous, as is also the adult. A common species is represented at
Fig. 33.
The Suborder EPHEMEROPTERA ([Greek: ephemeron], a day-fly; [Greek:
pteron], wing) comprises the May-flies, or Ephemeridae (see Fig. 42).
These insects are very fragile and are often attracted in enormous
numbers to electric lights. They have large front wings, while the hind
wings are small, rudimentary, or wanting. They are furnished with two or
three very long, jointed, threadlike caudal appendages. The larval and
nymphal stages are passed in the water and aquatic vegetation furnishes
the food, although some species may be predaceous. The adults have very
rudimentary mouths and eat nothing; their term of life is also very
limited, not exceeding 2-4 days.
[Illustration: FIG. 42.--A May-fly (_Potamanthus marginatus_). (From
Packard.)]
Suborder THYSANURA ([Greek: thysanos], tassel; [Greek: oura], tail).
This suborder comprises minute, degraded insects commonly known as
Spring-tails, Bristle-tails, Fish-moths, Snow-fleas, etc. They occur in
damp situations and also infest books, wall-paper, etc., eating the
starch paste in the book-bindings, or beneath the wall paper. They
comprise very primitive forms and are interesting because they are
supposed to represent the original stock from which the higher orders of
insects have sprung. They are wingless, usually with simple eyes, and
clothed with scales, and undergo no metamorphosis. Some of them, as the
Fish-moth (_Lepisma sp._), run very rapidly and are furnished at the end
of the body with a number of long bristles. In other forms these anal
bristles or stylets are united at the base and bent under the body and
become a powerful jumping organ, giving them the very appropriate name
of Spring-tails.
[Illustration: FIG. 43.--(_Lepisma 4-seriata_). (After Packard.)]