ON THE HABITS OF ANTS. 53 



rarely or never quit the nest, but receive their food from the work- 

 ers, and indeed appear to do nothing except hxy eggs. 



A nest of ants must not be confused with an ant-hill in the ordi- 

 nary sense. Very often, indeed, a nest has only one dwelling, and in 

 most species seldom more than three or four. Some, however, form 

 numerous colonies. M. Forel even found a case in which one nest of 

 F. exsecta had no less than two hundred colonies, and occupied a cir- 

 cular space with a radius of nearly two hundred yards. Within this 

 area they had exterminated all tlie other ants, except a few nests of 

 lapinoma erraticum^ which survived, thanks to their gi-eat agility. 

 In these cases the number of ants thus associated together must have 

 been enormous. Even in single nests Forel estimates the numbers at 

 from 5,000 to 500,000. 



In their modes of fighting, different species of ants have their sev- 

 eral peculiarities. Some, also, are much less military than others. 

 Myrmecina Latreillii, for instance, never attack, and scarcely even 

 defend themselves. Their skin is very hard, and they roll themselves 

 into a ball, not defending themselves even if their nest is invaded : 

 to prevent which, however, they make the entrances small, and often 

 station at each a worker, who uses her head to stop the way. The 

 smell of this species is also, perhaps, a protection. Tetramorium cms- 

 pitum has the habit of feigning death. This species, however, does 

 not roll itself up, but merely applies its legs and antennse closely to 

 the body. 



Formica rufa^ the common horse ant, attacks in serried masses, 

 seldom sending out detachments, while single ants scarcely ever make 

 individual attacks. They rarely pursue a flying foe, but give no quar- 

 tei", killing as many enemies as possible, and never hesitating, with 

 this object, to sacrifice themselves for the common good. 



Formica sayiguinea, on the contrary, at least in their slave-making 

 expeditions, attempt rather to terrify than to kill. Indeed, when they 

 are invading a nest, they do not attack the flying inhabitants unless 

 they are attempting to carry off pupoe, in which case they ai'e forced 

 to abandon the pupae. When fighting, they attempt to crush their 

 enemies with their mandibles. 



Formica exsecta is a delicate but very active species. They, also, 

 advance in serried masses, but in close quarters they bite right and 

 left, dancing about to avoid being bitten themselves. When fighting 

 with larger species they spring on to their backs, and then seize them 

 by the neck or by an antenna. They also have the instinct of com- 

 bining in small parties, three or four seizing an enemy at once, and 

 then pulling difierent ways, so that she, on her part, cannot get at any 

 one of her foes. One of them then jumps on her back and cuts, or 

 rather saws, ofi" her head. In battles between this ant and the much 

 larger F. pratensis, many of the latter may be seen, each with a little 

 F. exsecta on her back, sawing ofi" her head from behind. 



