ON THE HABITS OF ANTS. 45 



stupid creatures will starve in the midst of plenty rather than feed 

 themselves. I have had a nest of this species under observation for 

 a long time, but never saw one of the masters feeding, I have kept 

 isolated specimens for weeks by giving them a slave for an hour or 

 two a day to clean and feed them, and under these circumstances 

 they remained in perfect health, while but for the slaves they would 

 have perished in two or three days. I know no other case in Nature 

 of a species having lost the instinct of feeding. 



In P. rufescens^ the so-called workers, though thus helpless and 

 stupid, are numerous, energetic, and in some respects even brilliant. 

 In another slave-making species, however, Strongylognathus, the 

 workers are much less numerous, and so weak that it is an unsolved 

 probtem how they contrive to make slaves. 



Lastly, in a fourth species, Anergetes atratulus^ the workers are 

 absent, the males and females living in nests with workers belonging 

 to another ant, Tetraynoriutn ccespitum. In these cases the Tetra- 

 moriums, having no queen, and consequently no young of their own, 

 tend the young of the Anergetes. It is, therefore, a case analogous 

 to that of Polyergus, but it is one in which slave-owning has almost 

 degenerated into parasitism. It is not, however, a case of true para- 

 sitism, because the Tetramoriiims take great care of the Anergetes.^ 

 and, if the nest is disturbed, carry them off to a place of safety. 



M. Forel, in his excellent work on ants, has pointed out that very 

 young ants devote themselves at first to the care of the larvae and 

 pupae, and that they take no share in the defense of the nest or 

 other out-of-door work until they are some days old. This seems 

 natural, because at first their skin is comparatively soft ; and it 

 would clearly be undesirable to undertake rough work or run 

 into danger until their armor had had time to harden. There 

 are, however, reasons for thinking that the division of labor is 

 carried still further. I do not allude merely to those cases in which 

 there are completely different kinds of workers, but even to the 

 ordinary workers. In L. flavus, for instance, it seems probable that 

 the duties of the small workers are somewhat different from those 

 of the large ones, though no such division of labor has yet been 

 detected. In F. fusca I made an observation which surprised me 

 very much. In the autumn of 1875 I noticed an ant out feeding 

 alone. The next day the same ant was out by herself, and I could 

 easily recognize her because by some accident she had lost the 

 claws of one of her hind-feet. My attention being roused, I watched 

 the nest for some weeks, and saw this same ant out repeatedly, but 

 no other. This winter I have kept two nests under close observation 

 that is, I arranged with my daughters and their governess. Miss 

 Wendland, most conscientious observers, that we should look at the 

 nest once every hour throughout the day, and this has been done 

 since the middle of November, with a few exceptions not enough 



