68 NATURAL HISTORY. [cH. III. 



best adapted for the completion of its work, that the 

 insect is as mechanical as ingenious. 

 A B 



Reaumur wondered, at this stage of the building, 

 what form the cocoon would ultimately exhibit, 

 thinking that additional appendages would be affixed 

 to these at different angles, so as to form a kind of 

 perpendicular roof ; but the insect's ideas of archi- 

 tecture were different from any which Reaumur had 

 fancied, for the little workman destined these two 

 wings alone to form a case perfectly closed, and 

 these two were amply sufficient for its purpose. 



The chief object of the insect was now perceived 

 to be to bring the outer edges of these two wings to- 

 gether, just as we shut a pair of folding or cupboard 

 doors, when they are opened and pushed backwards. 

 Hence we may judge with what mechanical skill 

 and precision the insect must form these two wings ; 

 for unless they are made of a proper size while 



