The Modern Theory of Instinct 373 



supplied with Buprestis-beetles persists in the 

 fare which she has adopted and serves her larva 

 with Buprestis-beetles. One Sphex must have 

 Crickets ; a second, Grasshoppers ; a third, 

 Locusts. Nothing is accepted but these par- 

 ticular dishes. The Bembex who hunts Gad- 

 flies revels in them and refuses to do without 

 them, whereas Stizus ruficornis, who fills the 

 larder with Praying Mantes, scorns any other 

 game. And so with the rest. They have each 

 their own taste. 



It is true that many allow themselves a more 

 varied bill of fare, but only within the limits of 

 one entomological group : thus the Weevil and 

 Buprestis hunters prey upon any species pro- 

 portioned to their strength. Were the Hairy 

 Ammophila to make a change in her diet, that 

 would be her case too. Whether small and 

 sundry to each cell or large and single, the prey 

 would always consist of caterpillars. So far, 

 so good. But there remains the question of the 

 many replaced by the unit ; and I do not yet 

 know one instance of such an alteration in the 

 Wasp's habits. She who stocks the burrow 

 with a single joint never thinks of heaping up 

 several of smaller size ; she who goes on re- 

 peated expeditions to stack a quantity of game 

 in the same cell does not know how to limit her- 

 self to one head by choosing larger meat. The 



