MODES OF FIGHTING. 17 



vent which 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. Tetramoriu'm ccespitum has the habit of 

 feigning death. This species, however, does not roll 

 itself up, but merely applies its legs and antennsa 

 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 quarter, 

 killing as many enemies as possible, and never hesi- 

 tating, with this object, to sacrifice themselves for the 

 common good. 



Formica sariguinea, on the contrary, at least in 

 their slave-making expeditions, attempt rather to 

 terrify than to kill. Indeed, when invading a nest, 

 they do not attack the flying inhabitants unless these 

 are attempting to carry off pupae, in which case the 

 F, sanguineas force them 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 acting together, three 



