, in reply, suggested
their interpretation as warning colours, a suggestion since verified by
experiment (_Proc. Ent. Soc. Lond._, 1867, p. lxxx; _Trans. Ent. Soc.
Lond._, 1869, pp. 21 and 27). Although animals with warning colours are
probably but little attacked by the ordinary enemies of their class,
they have special enemies which keep the numbers down to the average.
Thus the cuckoo appears to be an insectivorous bird which will freely
devour conspicuously coloured unpalatable larvae. The effect of the
warning colours of caterpillars is often intensified by gregarious
habits. Another aposematic use of colours and structures is to divert
attention from the vital parts, and thus give the animal attacked an
extra chance of escape. The large, conspicuous, easily torn wings of
butterflies and moths act in this way, as is found by the abundance of
individuals which may be captured with notches bitten symmetrically out
of both wings when they were in contact. The eye-spots and "tails" so
common on the hinder part of the hind wing, and the conspicuous apex so
frequently seen on the fore wing, probably have this meaning. Their
position corresponds to the parts which are most offen found to be
notched. In some cases (e.g. many _Lycaenidae_) the "tail" and eye-spot
combine to suggest the appearance of a head with antennae at the
posterior end of the butterfly, the deception being aided by movements
of the hind wings. The flat-topped "tussocks" of hair on many
caterpillars look like conspicuous fleshy projections of the body, and
they are held prominently when the larva is attacked. If seized, the
"tussock" comes out, and the enemy is greatly inconvenienced by the fine
branched hairs. The tails of lizards, which easily break off, are to be
similarly explained, the attention of the pursuer being probably still
further diverted by the extremely active movements of the amputated
member. Certain crabs similarly throw off their claws when attacked, and
the claws continue to snap most actively. The tail of the dormouse,
which easily comes off, and the extremely bushy tail of the squirrel,
are probably of use in the same manner. Animals with warning colours
often tend to resemble each other superficially. This fact was first
pointed out by H. W. Bates in his paper on the theory of mimicry
(_Trans. Linn. Soc._ vol. xxiii., 1862, p. 495). He showed that the
conspicuous, presumably unpalatable, tropical American butterflies,
belonging to