250 ORIGIN OF THE HABITS OF SPHEX. 



ancestral Sphex restricted itself to one victim, and 

 that its descendants ^^subdivises en groupes et con- 

 stitues enfin en aiitant d'especes distinctes par le lent 

 travail des siecles, se sont avises qu'en dehors dii 

 comestible des ancetrcs il y avait ime foule d'autres 

 aliments." 



This, he says, supposes that they experimented on 

 various victims, found several of them to their liking, 

 and then, after a period of varied and plentiful diet, 

 voluntarily abandoned so great an advantage. 



"Avoir decouvert, par vos essais d'age en age, la 

 variete de I'alimentation ; i'avoir pratiquee, au grand 

 avantage de votre race, ct finir par I'uniformite, cause 

 de decadence ; avoir connu I'exceilent et le repudier 

 pour le mediocre, * Oh ! mes Sphex, ce serait stupid e si 

 le transformisme avait raison. ' " 



" J'estime," then he concludes, " que votre ancetre 

 commun, votre precurseur, a gouts simples ou bien a 

 gouts multiples, est une pure chime re." 



Ko doubt the habits of Hymenoptera present many 

 difficulties, and have undoubtedly many surprises in 

 store for us, and I cannot think the matter is so clear 

 as M. Fabre imagines, or that he has exhausted the 

 possible cases. It is possible, though it is, I admit, 

 only a supposition, that the ancestral Sphex hunted 

 some species which does not now exist — at least not in 

 the south of France — and which might have disappeared 

 gradually. As it became rarer, they might be driven 

 to attack other prey, and M. Fabre has himself shown 

 by a variety of most ingenious experiments that the 

 larvae are by no means fastidious as to their food. The 

 Hymenoptera vary considerably in size, and the larger 

 individuals might be able to overmaster some large 



