IN CATERPILLARS 161 



to be noticed that in general all vivid colors are 

 subdued and entirely neutral tints assumed. 



There are many instances among other cater- 

 pillars where most extraordinary resemblances are 

 assumed, very probably protective in their nature. 

 Indeed, in some of our own swallow-tails the mark- 

 ings of the front part of the body may very likely 

 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 caterpillars 

 which possess features of a very surprising charac- 

 ter, doubtless for the sake of protection ; one of 

 the commonest of which is the striking contrast 

 between creamy white and black, or some other 

 dark tint, which makes the creature resemble the 

 vermiform dropping of a bird ! This is true of 

 all our species of Basilarchia, of the Green Comma 

 (Polygonia f annus), and, especially in their middle 

 ' stages, of several of the Papilioninae, such as the 

 Green Clouded Swallow-tail (Euphoeades troilus) 

 and the Giant Swallow-tail (Heraclides cresphon- 

 tes). 



All these mimetic colors are of advantage only 

 as against their vertebrate enemies. M'Lacldan 

 has pointed out, what every observer must discover, 



