/ 

 1146 THE BUTTERFLIES OF NEW ENGLAND. 



fact tliat in a mitiibcr of our caterpillars and particularly in those of the 

 Papilioninac, an entire change of color takes place just previous to pupa- 

 tion. The period of pupation is probably the most hazardous for an in- 

 sect, as far as its active external foes are concerned, it being absolutely 

 helpless in this period and in a very sensitive state. The time required 

 for the change is much greater in any one species than for ordinary ecdysis 

 in the same species ; and whatever the purpose of the change in coloration 

 may be, it will hardly fail to he noticed that in general all vivid colors are 

 subdued and entirely neutral tints assumed. 



There are many instances arnong other caterpillars where most extraor- 

 dinary resemblances are assumed, very probably protective in their nature. 

 Indeed in some of our own swallow tails the markings of the front part of the 

 body may very hkely serve to alarm a foe about to attack, as they are 

 really of a very striking nature, especially when the creature assumes the 

 attitude which it does when disturbed. We have, moreover, some cater- 

 pillars which possess featui-es of a very surprising character, doubtless for 

 the sake of protection ; one of the commonest of which is the striking con- 

 trast between creamy white and black, or some otlier dark tint, which 

 makes the creature resemble the vermiform dropping of a bird ! This is true 

 of all our species of Basilarchia, of Polygonia faunas and, especially in 

 their middle stages, of several of the Papilioninac, such as Euphoeades 

 troilus and Heraclides cresphontes. 



All these mimetic colors ai-e of advantage only as against their verte- 

 brate enemies. M'Lachlan has pointed out, what every observer must 

 discover, that they give the insect no exemption whatever from the attack 

 of ichneumons, — a fact wliich is perfectly in accord with our knowledge of 

 the physiology of insect-vision. But as regards their more highly organized 

 enemies, it may indeed be doubted whether there is a single one of 

 our butterfly caterpillars which is not protected by means of its color, 

 either to prevent its being seen or to render it conspicuous. Indeed 

 we are inclined to say with Drummond that "mimicry is not an occasional 

 or exceptional phenomenon, but an integral part of the economy of nature. 

 It is not a chance relation between a few objects, but a system so widely 

 authorized that probably the whole animal kingdom is more or less involved 

 in it." (Trop. Africa, 178-179.) 



BIBLIOGRAPHY. 



Lubbock, Sir J. On plants and insects. In his Scientific lectures. London, 1879. 



Poulton, E. B. In his various papers on the markings of leijidopterous larvae and kindred 

 topics in the Trans, ent. so<-. Lond., 1883-1888, and in the Proceedings of the Royal and of the 

 Zoological societies of London, 1885-1887. 



Wallace, A. R. The colours of animals and sexual selection. In his Tropical nature and 

 other essays. London, 1878. 



Weismann, A. The origin of the markings of caterpillars. In his Studies in the theory of 

 descent. London, 1882. 



