There are many other curious modifications of it, but these will be best appreciated after we have discussed the remarkable phenomenon of "mimicry," which is bound up with and altogether depends upon "warning colour," and is in some cases the chief indication we have of the possession of some offensive weapon to secure the safety of the species imitated.
_Mimicry._ This term has been given to a form of protective resemblance, in which one species so closely resembles another in external form and colouring as to be mistaken for it, although the two may not be really allied and often belong to distinct families or orders.

One creature seems disguised in order to be made like another; hence the terms "mimic" and mimicry, which imply no voluntary action on the part of the imitator.

It has long been known that such resemblances do occur, as, for example, the clear-winged moths of the families Sesiidae and Aegeriidae, many of which resemble bees, wasps, ichneumons, or saw-flies, and have received names expressive of the resemblance; and the parasitic flies (Volucella) which closely resemble bees, on whose larvae the larvae of the flies feed.
The great bulk of such cases remained, however, unnoticed, and the subject was looked upon as one of the inexplicable curiosities of nature, till Mr.Bates studied the phenomenon among the butterflies of the Amazon, and, on his return home, gave the first rational explanation of it.[98] The facts are, briefly, these.

Everywhere in that fertile region for the entomologist the brilliantly coloured Heliconidae abound, with all the characteristics which I have already referred to when describing them as illustrative of "warning coloration." But along with them other butterflies were occasionally captured, which, though often mistaken for them, on account of their close resemblance in form, colour, and mode of flight, were found on examination to belong to a very distinct family, the Pieridae.

Mr.Bates notices fifteen distinct species of Pieridae, belonging to the genera Leptalis and Euterpe, each of which closely imitates some one species of Heliconidae, inhabiting the same region and frequenting the same localities.