Fig. 3.—The Caterpillar of the Elephant Hawk-Moth (Chærocampa elpenor). Full grown. Natural size.
Fig. 4.—The Caterpillar of the Elephant Hawk-Moth (Chærocampa elpenor). First stage.
Let us begin with the Elephant Hawk-moth. The caterpillars ([Fig. 3]), as represented in most entomological works, are of two varieties, most of them brown, but some green. Both have a white line on the three first segments; two remarkable eye-like spots on the fourth and fifth, and a very faint median line; and are rather more than four inches long. I will direct your attention specially, for the moment, to three points:—What do the eye-spots and the faint lateral line mean? and why are some green and some brown, offering thus such a marked contrast to the leaves of the small epilobe on which they feed? Other questions will suggest themselves later. I must now call your attention to the fact, that when the caterpillars first quit the egg, and come into the world ([Fig. 4]), they are quite different in appearance, being, like so many other small caterpillars, bright green, and almost exactly the color of the leaves on which they feed. That this color is not the necessary or direct consequence of the food, we see from the case of quadrupeds, which, as I need scarcely say, are never green. It is, however, so obviously a protection to small caterpillars, that this explanation of their green color suggests itself to every one.
