IT.] CH^ROCAMPA ELPENOR. 53 



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 Epilobium parvum, 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. 37), they are 



FIG. 38. Chcerocampa clptnor. Second stage. 



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 a 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 the explanation of 

 their green color suggests itself to every one. After 

 five or six days, and when they are about a quarter of 

 an inch in length, they go through their first moult. 

 In their second stage (Fig. 38), they have two white lines, 



FIG. 39. Chccrocampa elpenor. Just before second moult. 



stretching along the body from the horn to the head ; 

 and after a few days (Fig. 39), but not at first, traces 



