5o8 THE POPULAR SCIENCE MONTHLY. 



consequent value which they set upon them, mcluce the animals, when 

 supplies are scarce, to plunder one another's nests, prolonged warfare 

 being the result. Thus Moggridge says : " By far the most savage 

 and prolonged contests which I have witnessed were those in which the 

 combatants belonged to two different colonies of the same species. . . . 

 The most singular contests are those which are waged for seeds by A. 

 harhara, when one colony plunders the stores of an adjacent nest 

 belonging to the same species ; the weaker nest making prolonged, 

 though, for the most part, inefficient attempts to recover their prop- 

 erty." In one case the predatory war lasted for forty-six days, during 

 which time it became evident that the attacking nest was the stronger, 

 for 



streams of ants laden with seeds arrived safely at the upper nest, while close 

 observation showed that very few seeds were successfully carried on the reverse 

 journey into the lower or plundered nest. Thus, when I fixed my attention on 

 one of these robbed ants surreptitiously making its exit with the seed from the 

 thieves' nest, and having overcome the oppositions and dangers met with on 

 its way, reaching, after a journey which took six minutes to accomplish, the 

 entrance to its own home, I saw that it was violently deprived of its burden by 

 a guard of ants stationed there apparently for the purpose, one of whom in- 

 stantly started oft' and carried the seed all the way back again to the upper nest. 

 . . . After the 4th of March I never saw any acts of hostility between these 

 nests, though the robbed nest was not abandoned. In another case of the same 

 kind, however, where the struggle lasted thirty-two days, the robbed nest was 

 at length completely abandoned. 



Lastly, McCook records the history of an interesting engagement 

 which he witnessed between two nests of Tetramorium ccesjntum in 

 the streets of Philadelphia, and which lasted for nearly three weeks. 

 Although all the combatants belonged to the same species, friends 

 were always distinguished from foes, however great the confusion of 

 the fight. This fact is always observable in the case of battles between 

 nests of the same species, and McCook thinks that the distinction ap- 

 pears to be effected in some way by contact of antennae. 



Keeping Pets. Many species of ants display the curious habit of 

 harboring in their nests sundry kinds of other insects, which, so far as 

 observation extends, are of no benefit to the ants, and which have 

 therefore been regarded by observers as mere domestic pets. These 

 pets are, for the most part, species which occur nowhere else except 

 in ants' nests, and each species of pet is peculiar to certain species of 

 ant. Beetles and crickets seem to be the more favorite kinds of in- 

 sects, and these live on the best terms with their hosts, playing round 

 the nests in fine weather, and retiring into them in stormy weather, 

 while allowing the ants to carry them from place to place during mi- 

 grations. It is evident, therefore, that ants not only tolerate these 

 insects, but foster them ; and, as it seems absurd to credit the ants 

 with any mere fancy or caprice, such as that of keeping pets, it is per- 



