~;i4 ANIMAL COLOEATION. 



generally a larger, softer, body than a Iratterfly, and is in con- 

 sequence more worth eating than a butterfly, which is chiefly 

 wing. It is stated that in the troi)ics butterflies are greatly 

 sought after by birds. But even in temperate regions they are by 

 no means entirely avoided. Prof. Eimer * relates the following 

 incident which bears upon the matter : — " Some years ago . . . 

 on a hot summer's day, I was on the high plateau of the 

 Swabiau Alp ; far and wide no water was visible, but at one 

 spot in the field path there ran over it the outflow of a 

 little spring, forming a shallow, clear pool in the track. Here 

 sat himdreds of butterflies, all whites and blues, closely crowded 

 together, drinking thirstily. On my approach a number of 

 birds (stone chats) flew from the spot, and when 1 came up I 

 found a number of maimed butterflies lying fluttering on the 

 ground ; jjieces had been bitten from the wings of most of 

 them — indeed, the wings were often torn to pieces before the 

 birds succeeded in getting the bodies of the butterflies, although 

 hese were sitting quietly on the ground." 



Mimicry possibly Originated between Forms much alike to 

 start with. 



If it be difficult to understand how the wonderfally perfect 

 copying of one insect by another— that " palpably intentional 

 likeness that is perfectly staggering, ' as Mr. Bates wrote in 

 an oft-quoted passage— has been brought about, it is harder 

 .still to understand the first commencement and the early 

 stages of the development of the mimicry. Probably, however, 

 mimicry is always based upon a considerable initial resem- 

 blance. 



To take, for example, the classical instance of mimicry, that 

 of the Heliconida3 by the Pierida3 ; the typical Pierid (our 

 * "Organic Evolution," Eng. trans, by Cunningham, p. 118. 



