Change of Diet 



Hunting Wasp is confined to a certain genus 

 of game, which is usually strictly limited. 

 She pursues her appointed quarry and re- 

 gards anything outside it with suspicion and 

 distaste. The tricks of the experimenter, 

 who drags her prey from under her and flings 

 her another in exchange, the emotions of the 

 possessor deprived of her property and im- 

 mediately recovering it, but under another 

 form, are powerless to put her on the wrong 

 scent. Obstinately she refuses whatever is 

 alien to her portion; instantly she accepts 

 whatever forms part of it. Whence arises 

 this insuperable repugnance for provisions 

 to which the family is unaccustomed? Here 

 we may appeal to experiment. Let us do so : 

 its dictum is the only one that can be trusted. 

 The first idea that presents itself and the 

 only one, I think, that can present itself is 

 that the larva, the carnivorous nurseling, has 

 its preferences, or we had better say its ex- 

 clusive tastes. This kind of game suits it; 

 that does not; and the mother provides it 

 with food in conformity with its appetites, 

 which are unchangeable in each species. 

 Here the family dish is the Gad-fly; else- 

 where it is the Weevil; elsewhere again it is 

 the Cricket, the Locust and the Praying 

 Mantis. Good in themselves, in a general 

 i8s 



