INSTINCT OF INSECTS. 521 



impeded its progress. Upon this it alighted again on 

 the gravel walk, deliberately sawed off first one wing 

 and then the other; and having thus removed the cause 

 of its embarrassment, flew oft' with its booty ^. Could 

 any process of ratiocination be more perfect ? " Some- 

 thing acts upon the wings of this fly and impedes my 

 flight. If I wish to reach my nest quickly, I must get 

 rid of them — to eftect which, the shortest way will be 

 to alight again and cut them off." These reflections, 

 or others of similar import, must be supposed to have 

 passed through the mind of the wasp, or its actions are 

 altogether inexplicable. Instinct might have taught 

 it to cut off the w ings of all flies, previously to flying 

 away with them. But here it first attempted to fly 

 with the wings on, — w as impeded by a certain cause, 

 — discovered what this cause was, — and alighted to re- 

 move it. The chain of evidence seems perfect in proof 

 that nothing but reason could have been its prompter. 



An analogous though less striking fact is mentioned 

 by Reaumur on the authority of M. Cossigny, who 

 witnessed it in the Isle of France where the Spheges 

 are accustomed to bury the bodies of cockroache;* 

 along with their eggs for provision for their young. 

 He sometimes saw one of these Spheges attempt to 

 drag after it into its hole a dead cockroach, which was 

 too big to be made to enter by all its efforts. After 

 several ineffectual trials the Sphexcame out, cut oft' its 

 elytra and some of its legs, and thus reduced in com- 

 pass drew in its prey withcit difliculty"'. 



Under this head 1 shall mention but one fact more. — 

 A friend of Gleditschthe observer of the singular eco- 



* Zoonomiay i. 183. '' Rcaum, vi. 283. 



