Of the families representing more than five thousand species, the chief
are the following:
(1) _Nymphalidæ_, the largest, containing between four and five thousand
species. They have a relatively simple type of coloration, and are
interesting because of their disposition to mimic other species. They
are distasteful to birds. They include the red admiral, the
tortoise-shells, the peacock, and so on, as well as the fritillaries and
the purple emperor. In it are also included the remarkable leaf
butterflies in which the under surface, in shape, color and markings,
closely resemble a dead leaf, while the upper surface is brightly
colored. On alighting only the under surface is visible.
(2) The _Erycinidæ_ is represented by the Duke of Burgundy fritillary.
(3) The _Lycænidæ_ include the “blues,” so commonly seen flitting near
the ground along muddy roads, so called from the color of the upper
surface, but many are also copper, white and yellow.
(4) The _Pieridæ_ include the white cabbage butterflies. They are
remarkable for the prevalence of white, yellow, and orange colors, and
for the fact that these tints are due to uric acid, or derivatives of
this substance, stored in the wings as a pigment.
(5) The _Papilionidæ_, or swallow-tails, contain perhaps the most
beautiful forms. The females are strikingly different from the males,
and though larger, do not display the same beauty of coloration. The
members of the family are widely distributed.
(6) The family _Hesperidæ_, or skippers, includes insects very different
from other butterflies, both in structure and habits. The adults have in
many cases a very rapid but jerky method of flight, and the larvæ in
their habits resemble moths rather than butterflies.
=Moths= (_Heterocera_).--The antennæ of moths are bristly, gradually
lessening from base to tip; when sitting the wings are turned down;
and its flight is nocturnal. What the owl is among birds, the moth
is among insects: it is a night-insect, carrying on its pursuits,
and exercising all its activity amid the gloom of darkness. So
numerous is the variety of moths, that there are upward of five
hundred species.
The giant OWL-MOTH of Brazil (_Thysania agrippina_) measures nearly
a foot across from tip to tip of expanded wings, while the smallest
are hardly visible to unaided eyes. The larvæ or caterpillars feed
mostly on living plants, and in this connection are very familiar;
others of these ravaging forms ruin clothes, furs, and the like.
Almost the only directly useful form is the silk-moth.
=Silkworm Moth.= See under Domesticated Animals.
=STRAIGHT-WINGED INSECTS= (_Orthoptera_)
The fore wings are either parchment-like or membraneous; the hind
wings always membraneous. The wings cover the body horizontally, and
do not meet in a straight line or ridge, as they do in the beetles.
This order of insects undergoes only a partial metamorphosis, being
produced from eggs in a wingless condition. The Cicadas, however,
are an exception, as they live in the ground frequently for years
in the larva state. In this order are included the locust, cricket,
grasshopper, cockroach, scale insect, plant-lice, and many kinds of
bugs.
=Crickets= (_Gryllus_) are akin to grasshoppers. They have long feelers,
a rasping organ on the wing-covers of the males, wings closely folded
lengthwise, but often along with the wing-covers degenerate, great
powers of leaping, and a retiring, more or less subterranean habit of
life. Many of the species are wingless, and it is the males only which
make a chirping sound. They are widely distributed, and all are
herbivorous. The field cricket, house cricket and the common
mole-cricket, are well-known representatives of the family.
=Earwigs= (_Forficula_) have two pairs of wings, very dissimilar, the
anterior pair being short and horny, the posterior pair folded
longitudinally and transversely; the mouth parts are well developed and
suited for biting; the antennae are thread-like; there is no true
metamorphosis in the life-history. The common earwig is best known for
the pincer-like organ at the end of the abdomen.
Earwigs avoid the light, and do most of their work in the dark. They
feed, as gardeners well know, on petals and other parts of flowers, on
fruit, seeds and leaves, nor is animal debris refused. They are usually
and readily caught in artificial shelters provided for their
destruction.
The eggs of the common species are laid in spring, fifteen to twenty, in
some convenient cavity. These are carefully watched, and even after the
birth of the young earwigs, the mother still tends them as a hen does
her chicks.
=Grasshopper=, a name given to numerous insects forming the locust
family. They usually live among vegetation, in woods and thickets or in
the open field. Most of them feed on flies and caterpillars, in catching
which they use their powerful fore-legs, but many affect plants, and
some combine both diets.
In the grasshopper the head is placed vertically; the slender antennae
are longer than the body; there are hemispherical eyes, but rarely
eye-spots; wings and wing-covers are generally present. The right (and
occasionally also the left) wing-cover of the male bears a clear, round
membrane stretched on a ring, which produces the well-known “chirp” when
set in vibration.
The females have a long egg-positor. The eggs are laid by means of it
either in the earth or in some dry stem. From these, in spring, larvæ
are developed, which are virtually like the adults, but molt at least
six times before they become full-grown.
=Katydid=, a name applied to numerous American insects, nearly related
to grasshoppers. They frequent trees, shrubbery, and grass, and are well
concealed in the foliage by their green color. In their general habit,
_e. g._ in the song to which the syllables “kat-y-did” refer, and in the
egg-laying accomplished by the long egg-positors of the female, these
lively insects resemble grasshoppers.
=Locusts= (_Acrididae_) are large, ground-loving insects, of world-wide
distribution, famous for their voracious vegetarian appetite. In size
they vary from one-quarter inch to five inches in length. They have
strong hind-legs with great leaping powers, large heads with formidable
mouth-organs, shorter antennæ and robuster bodies than grasshoppers.
Both winged and wingless forms occur, the former with strong powers of
flight. The females have strong egg-positors by which they bore holes
for their eggs. The numerous eggs are laid in holes drilled in the
ground; the young when hatched generally resemble the parents except in
the absence of wings. From the first they are gregarious, and
excessively voracious except during their repeated molts; they devour
all green things, and even one another, and are often forced by stress
of hunger and excessive multiplication to migrate in great swarms.
Their ravages sometimes cause widespread famine and ruin. One of the
most famous and destructive forms is the Rocky Mountain Locust
(_Caloptenus spretus_); the most abundant migratory species of the East,
so often mentioned in the Scriptures, is _Pachytylus migratorius_.
[Illustration: On the left is shown a Leaf Insect which, having given up
the habit of flight, has yet retained its likeness to the leaves upon
which it feeds to protect itself from its enemies. On the right is shown
a grasshopper depositing her eggs in a nest under the ground. (See
above).]
=ANTS, BEES AND WASPS= (_Hymenoptera_)
These membrane-winged insects are the most intelligent of their kind.
They are readily recognized by the presence of four transparent wings
traversed by a comparatively small number of veins, the hinder ones
being much smaller than the others, to which they are in many instances
attached during flight by means of a row of minute hooks. The posterior
end of the body in the female is commonly provided with a piercing
apparatus, which may either serve for boring holes, in which eggs are
laid, in which case it is called an “ovipositor,” or may have been
modified into a poisoned sting, useful for offense and defense. The
black and yellow or black and red bands of wasps and bees are “warning
colors,” indicating their stinging powers.
The larvæ either resemble caterpillars or are pale, helpless maggots,
devoid of limbs, for the welfare of which more or less elaborate
provisions are made by the mother insect. Later on a pupa stage is
reached, from which the winged adult ultimately emerges. The highest
members of the order live in communities comprising several casts.
=Ants= (_Formicidae_).--These familiar and intelligent diminutive
creatures are perhaps the most interesting of all insects, owing to
the extraordinary way in which they have become adapted to a great
variety of modes of life. All are social, and a community typically
consists of males, females, workers (of one or more kinds), and, it
may be, soldiers. The first two are generally provided with wings,
though those of the females are soon shed, but exceptions to this
occur, and some species may have both winged and wingless
individuals of one sex or the other. The first pair of jaws
(mandibles) are well or even excessively developed, and possess
unusually free powers of movement in accordance with the varied
functions they have to perform. In many cases the females (including
the workers) are provided with a sting.
Ants hatch out as helpless, limbless larvæ, which have to be fed and
carefully attended, either by the fertile females or the workers, as
the case may be. Feeding is rather a curious affair, for the nurse
possesses a sort of pouch (crop) connected with her gullet, and this
is used as a store from which nutriment can be squeezed up into the
mouth. Adults can feed one another in the same way, as also the
little beetles and other insects which are often found as guests in
their communities.