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 larve 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 
