A STUDY OF MIMICRY 21 



just this period that these special and extraor- 

 dinary provisions for their safety and for the 

 accomplishment, so far as the species is concerned, 

 of the end of their life are given them. All this 

 has been brought about for the sole purpose of 

 prolonging their aerial life for the exceedingly few 

 days which are necessary for pairing and the 

 deposition of eggs. The more we contemplate so 

 strange and perfect a provision, and the means 

 by which it is accomplished, the more are we 

 impressed with the capabilities of natural selec- 

 tion, and begin to comprehend how powerful an 

 element it has been in the development of the 

 varied world of beauty about us. 



