iv.] EXPERIMENTS WITH PUP^E. 109 



former no notice whatever was taken, I have, moreover, 

 repeatedly placed dead bees close to honey on which live 

 ones were feeding, but the latter never took the slightest 

 notice of the corpses. 



It is clear from the experiments recorded in the 

 present and in my last lecture, that ants recognize 

 all their fellows in the same nest, but it is very difficult 

 to understand how this can be effected. The nests 

 vary very much in size, but in several species 100,000 

 individuals may probably be by no means an unusual 

 number, and in some instances even this is largely 

 exceeded. Now it seems almost incredible that in such 

 nests every ant should know every other one by sight. 



It has been suggested, in the case of bees, that each 

 nest might have some sign or password. 



The whole subject is full of difficulty. It occurred 

 to me, however, that experiments with pupse might 

 throw some light upon it. Although the ants of different 

 nests are generally deadly enemies, still, if larvse or pupse 

 from one nest are transferred to another of the same 

 species, they are kindly received, and tended with ap- 

 parently as much care as if they really belonged to 

 the nest. In ant warfare, though sex is no protection, 

 the young are spared — at least when they belong to the 

 same species. Moreover, though the habits and disposi- 

 tion of ants are greatly changed if they are taken away 

 from their nest and kept in solitary confinement, or only 

 with a few friends, still under such circumstances they 

 will carefully tend any young which may be confided to 

 them. Now, if the recognition were effected by means 

 of some signal or password, then, as it can hardly be 

 supposed that the larvse or pupse would be sufficiently 



