488 
sence of a film of air under the skin. I put it under the 
microscope, and then, having added a drop of water witha 
pipette I put the instrument down and looked through the 
glass. To my astonishment, the insect was gone, and an 
empty skin only remained. I then caught a second speci- 
men, in a similar condition, and put it under the micro- 
scope, hoping to see it come out. Nor was | disappointed. 
Very few moments had elapsed, when I had the satis- 
faction of seeing the thorax open along the middle of the 
back ; the two sides 'urned over; the insect literally walked 
out of itself, unfolded its wings, and in an instant flew up 
to the window. Several times since, I have had the 
pleasure of witnessing this wonderful change, and it is 
really extraordinary how rapidly it takes place ; from the 
moment when the skin first cracks, not ten seconds are 
over before the insect has flown away. 
The Dragon-flies, or Horse-stingers, as they are some- 
times called, from a mistaken idea that they sting severely 
enough to hurt a horse, though in fact they are quite harm- 
less, also spend their early days in the water. The larvee 
are brown, sluggish, ugly creatures, with six legs. They 
feed on small water animals, for which they wait very 
patiently, either at the bottom of the water or on some 
water plant. The lower jaws are attached to a long 
folding rod, and when any unwary little wretch approaches 
too near the larva, this apparatus is shot out with great 
velocity, and the prey which comes within its reach sel- 
dom escapes. In their perfect condition, also, Dragon- 
flies feed on other insects, and may often be seen hawking 
round ponds. The so-called Ant-lion in many respects 
resembles the Dragon-flies, but the habits of the larvee are 
very dissimilar. They do not live in the water, but prefer 
dry places, where they bury themselves in the loose sand, 
and seize any little insect which passes, with their long 
jaws. The true Ant-lion makes itself a little pit in loose 
ground or sand, and buries itself at the bottom. Any inat- 
tentive little insect which steps over the edge of this pit 
immediately falls to the bottom, and is instantaneously 
seized by the Ant-lion. Should the insect escape and at- 
tempt to climb up the side of the pit, the Ant-lion is said 
to throw sand at it, knocking it down again. 
One other family of Neuroptera I must mention, the 
Hemerobiidze. The perfect insect is a beautiful, lace- 
winged, very delicate, green insect, something like a 
tender Dragonfly, and with bright green, very touching 
eyes. The females deposit their eggs on plants, not 
. directly on the plant itself, but attached to it by a long 
white slender footstalk. The Jarvee have six legs and pow- 
erful jaws, and make themselves very useful in destroying 
the Hopfly. 
The insects forming the order Trichoptera are well 
known in their larval condition, under the name of caddis 
worms. These larvze are not altogether unlike caterpillars 
in form, but they live in water—which is the case with very 
few lepidopterous larvze—and form for themselves cylin- 
drical cases or tubes, built up of sand, little stones, bits of 
stick, leaves, or even shells, They generally feed on ve- 
getable substances, but will also attack minute freshwater 
animals. When full grown, the larva fastens its case 
to a stone, the stem of a plant, or some other fixed sub- 
stance, and closes the two ends with an open grating 
of silken threads, so as to admit the free access of water, 
while excluding enemies. It then turns into a pupa, which 
bears some resemblance to the perfect insect, “ except 
that the antennz, palpi, wings and legs are shorter, en- 
closed in separate sheaths and arranged upon the breast.” 
The pupa remains quiet in the tube until nearly ready to 
emerge, when it comes to the surface, and in some cases 
creeps out of the water. It is not therefore so completely 
motionless as the pupa of Lepidoptera. 
The Diptera, or Flies, comprise insects with two wings 
only, the hinder pair being represented by minute club- 
shaped organs called halteres, Flies quit the egg 
generally in the form of fat, fleshy, legless grubs. They 
NATURE 
feed principally on decaying animal or vegetable matter, 
and are no doubt useful as scavengers. When full 
grown they turn into pupe which are generally inac- 
tive ; those of some gnats, however, swim about. Other 
species, as the gadflies, deposit their eggs on the bodies 
of animals, within which the grubs, when hatched, feed. 
The mouth is generally furnished with two hooks which 
serve instead of jaws, The pupz are of two kinds. In 
the true flies, the outer skin of the full-grown larva is 
not shed, but contracts and hardens, thus assuming the 
appearance of an oval brownish shell or case, within 
which the insect changes into a chrysalis. The pupz 
of the gnats, on the contrary, have the limbs distinct 
and enclosed in sheaths. They are generally inactive, 
but some of the aquatic species continue to swim about. 
One group of Flies, which is parasitic on horses, sheep, 
bats, and other animals, has been called the Pupipara, 
because it was supposed that they were not born until they 
had arrived at the condition of pupz. They come into the 
world in the form of smooth ovate bodies, much resem- 
bling ordinary dipterous pupz, but as Leuckart has 
shown,* they are true, though abnormal, larve. 
The next order, that of the Aphaniptera, is very small 
in number, containing only the different species of Flea. 
The larva is long, cylindrical, and legless ; the chrysalis 
is motionless, and the perfect insect is too well known, at 
least as regards its habits, to need any description. 
Unlike the preceding orders of insects, the Heteroptera 
quit the egg in a form, differing trom that of the perfect 
insect principally in the absence of wings. The species 
constituting this group though very numerous, are generally 
small, and not so familiarly known to us as those of the 
other large orders, with indeed one exception, the well- 
known Bug. This was not, apparently, an indigenous 
insect, but seems to have been introduced. Shakespeare 
uses the word several times, but always in the sense of a 
bugbear, and not with reference to this insect. In this 
country it never acquires wings, but is stated to do so 
sometimes in warmer countries. The Heteroptera can- 
not exactly be said either to sting or bite. The jaws, of 
which, as usual among insects, there are two pairs, are 
| April 24, 1873. 
like needles, which are driven into the flesh, and the ~ 
blood is then sucked up the lower lip, which has the form 
of atube. This peculiar structure of the mouth prevails 
throughout the whole order ; consequently their nutri- 
ment consists almost entirely of the juices of animals or 
plants. In their metamorphoses the Heteroptera re- 
semble the Orthoptera; they are active through life, 
and the young resemble the perfect insects except in 
the absence of wings, which are gradually acquired. 
The majority are dull in colour, though some few are 
very beautiful. The Homoptera agree with the Hete- 
roptera in the structure of the mouth, and in the meta- 
morphoses. They differ principally in the front wings, 
which in Homoptera are membranous throughout, while 
in the Heteroptera the front part is thick. As in the 
Heteroptera, however, so also in the Homoptera, some 
species do not acquire wings. The Cicada, so cele- 
brated for its song, and the lanthorn fly, belong to this 
group. So also does the so-called Cuckoospit, so common 
in our gardens, which has the curious faculty of secreting 
round itself a quantity of frothy matter which serves to 
protect it from its enemies. But the best known insects 
of this group are the Aphides, or Plant-lice; while the 
most useful belong to the Coccidz, or scale insects, from 
one species of which we obtain the substance called lac, 
so extensively used in the manufacture of sealing- 
wax and varnish. Several species also have been used 
in dyeing, especially the Cochineal insect of Mexico, a 
species which lives on the Cactus. The male Coccus is a 
minute, active insect, with four comparatively large wings, 
while the female, on the contrary, never acquires wings, 
* Die Fortpflanzung und Entwickelung der Pupiparen, Von Dr, Ry 
Leuckart. (Halle, 1848.) 
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