Page:The naturalist on the River Amazons 1863 v1.djvu/325

 so as to resemble the soil, leaf, or bark on which it lives; the resemblance serving to conceal the creatures from the prying eyes of their enemies; or, if they are predaceous species, serving them as a disguise to enable them to approach their prey. When an insect, instead of a dead or inorganic substance, mimicks another species of its own order, and does not prey, or is not parasitic, may it not be inferred that the mimicker is subject to a persecution by insectivorous animals from which its model is free? Many species of insects have a most deceptive resemblance to living or dead leaves; it is generally admitted, that this serves to protect them from the onslaughts of insect-feeding animals who would devour the insect, but refuse the leaf. The same might be said of a species mimicking another of the same order; one may be as repugnant to the tastes of insect persecutors, as a leaf or a piece of bark would be, and its imitator not enjoying this advantage would escape by being deceptively assimilated to it in external appearances. In the present instance, it is not very clear what property the Callithea possesses to render it less liable to persecution than the Agrias, except it be that it has a strong odour somewhat resembling Vanilla, which the Agrias is destitute of. This odour becomes very powerful when the insect is roughly handled or pinched, and if it serves as a protection to the Callithea, it would explain why the Agrias is assimilated to it in colours. The resemblance, as before remarked, applies chiefly to the upper side; in other species it is equally close on both surfaces of the wing's. Some birds, and the