THE EVOLUTION OF INSTINCT 119 



motionless food In this case it is absolutely im- 

 possible that the animal has arrived at its habit otherwise 

 than by reflection upon the facts of experience." 



The careful studies of the Peckhams on the instincts of the 

 solitary wasps have shown that many of the assumptions 

 upon which Eimer rests his argument are erroneous. In 

 the first place the Peckhams found that the insects stored as 

 food were by no means uniformly paralyzed and that in 



FIG. 12. The wasp Ammophila stinging a caterpillar. (After Peckham. ) 



most nests several caterpillars died. Even where all were 

 dead the wasp larva? fed upon them, so that it is open to 

 question if much is gained by having the prey in a paralyzed 

 condition. The Peckhams conclude that "the primary 

 purpose of the stinging is to overcome resistance and to 

 prevent the escape of the victims, and that incidentally some 



