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INSECTS. 
to learn wisdom, since many of the problems of modern civilisation, involved in 
the questions concerned in the regulation of increase of population, the proper 
division of labour, and the support of useless individuals, have been satisfactorily 
solved by many of the species of insects that live habitually in communities. 
Speaking in a general way, insects may be said to be terrestrial animals, since 
all the species are fitted more or less completely for atmospheric respiration and for 
progression on the land; many of them in addition are furnished with wings, which 
propel them through the air with amazing velocity. In many of the orders, how¬ 
ever, as, for instance, in the beetles and bugs, there are species that have adopted 
an aquatic mode of life and spend their days in fresh-water ponds and streams in 
various quarters of the globe. Others again, like some of the gnats and dragon¬ 
flies, live in fresh-water during the larval stages of their existence, but quit it on 
attaining maturity. Insects, too, are sometimes found on the coast beneath stones 
and seaweed at low water, but there is only one species of insect that can strictly 
be called marine; this is a bug ( Halobates ) sometimes met with in numbers on 
the surface of the ocean thousands of miles from land. 
The phenomena known as mimicry and protective resemblance 
Mimicry. L */ ± 
are strikingly exemplified in insect life. The term mimicry is usually 
applied to cases where a species, otherwise unprotected, lives unmolested owing to 
its resemblance to another which is gifted with defensive weapons in the form of 
poison-glands, or with a nauseating flavour that renders it distasteful. Such species 
as these are usually rendered conspicuous by contrasting patches of bright colour. 
It is noticeable, for instance, that the patterns of bees and wasps are strikingly 
diversified, in order that the insects may be readily recognised and not slain by 
mistake for other species. Bees and wasps, then, being species that enjoy 
immunity from attack, are often imitated or mimicked by perfectly harmless flies 
and moths, and some beetles and animals allied to crickets similarly mimic ants. 
But the phenomenon of protective resemblance — or the mimicry of inanimate 
objects—by which a species is rendered practically invisible amongst its surround¬ 
ings on account of its resemblance to a leaf, stone, twig, or bird-dropping, is of far 
commoner occurrence. On the accompanying Plate a few instances of this kind 
of adaptation to surroundings are portrayed. Figs. 12, 13, and 18 are the 
larvas or caterpillars of different species of Lepidoptera, the first two in colour and 
shape simulating branches, and the last a snail-shell; Figs. 1, 2, 9 and 14 are 
leaf-like pupae or chrysalids of other kinds of Lepidoptera; while Figs. 3, 5, 7, 11, 
15, 23, and 24 are the adult stages of members of the same order under different 
disguises. The most noticeable of these is Fig. 11, representing a large and 
handsome butterfly, which, when at rest with its wings folded back, exactly 
resembles a dead leaf, even to the midrib and stem; while Figs. 23 and 24, exhibit 
two small moths, which might be readily mistaken for bird-dung. In the 
Orthoptera, as the insects allied to the cockroaches and grasshoppers are called, 
the phenomenon is carried to an extent elsewhere unsurpassed in the animal 
kingdom. This is well shown in the case of the leaf-insect (Fig. 4), the stick- 
insect (Fig. 8), and the leaf-like locust (Fig. 10). Most of the other figures on 
the Plate are of less importance. Attention, however, may be drawn to the water- 
bug (Fig. 16), the young dragon-fly (Fig. 6), the beetle (Fig. 19), the curious bugs 
