pair of feet which are slender and inconspicuous. The irregular
outline of the wings gives exactly the perspective effect of a
shrivelled leaf." The wonderful "stick insects" in like manner
mimic the twigs of the trees among which they lurk. Nor need we go
abroad in search of examples, for among our own insects are
countless instances of marvellous resemblances to the inanimate or
vegetable objects upon which they rest. One of the most interesting
is that of the geometer caterpillars, which are very plentiful, and
any one can observe them for himself even in a London garden. They
support themselves for hours by means of their posterior legs,
forming an angle of various degrees with the branch on which they
are standing and looking for all the world like one of its twigs.
The long cylindrical body is kept stiff and immovable, with the
separations of the segments scarcely visible, and its colour is
obscure and similar to that of the bark of the tree. Kirby and
Spence tell of a gardener mistaking one of these caterpillars for a
dead twig, and starting back in great alarm when, on attempting to
break it off, he found it was a living animal.

Sometimes concealment is secured by the aid of adventitious
objects. Many lepidopterous larvae live in cases made of the
fragments of the substances upon which they feed; and certain
sea-urchins cover themselves so completely with pebbles, shells,
and so forth, that one can see nothing but a heap of little stones.
Perhaps, however, the most interesting instance is the crab
described by Mr. Bateson, which "takes a piece of weed in his two
chelae and, neither snatching nor biting it, deliberately tears it
across, as a man tears paper with his hands. He then puts one end
of it into his mouth, and after chewing it up, presumably to soften
it, takes it out in the chelae and rubs it firmly on his head or