ANTS AND ANT LIFE. 157 



to ascertain whether F. sanguinea could distinguish the 

 pupa3 of F. fusca, which they habitually make into slaves, 

 from those of the little and furious F. flava, which they 

 rarely capture, and it was evident that they did at once 

 distinguish them : for we have seen that they eagerly and 

 instantly seized the pupa3 of F. fusca, whereas they were 

 much terrified when they came across the pupa?, or even the 

 earth from the nest of F. flava, and quickly ran away ; but 

 in about a quarter of an hour, shortly after all the little 

 yellow ants had crawled away, they took heart and carried 

 off the pupae. 



" One evening I visited another community of F. san- 

 guinea, and found a number of these ants returning home 

 and entering their nests, carrying the dead bodies of F. 

 fusca (showing that it was not a migration) and numerous 

 pupse. I traced a long file of ants burthened with booty, 

 for about forty yards, to a very thick clump of heath, 

 whence I saw the last individual of F. sanguinea emerge, 

 carrying a pupa ; but I was not able to find the desolated 

 nest in the thick heath. The nest, however, must have been 

 close at hand, for two or three individuals of F. fusca were 

 rushing about in the greatest agitation, and one was perched 

 motionless with its own pupa in its mouth on the top of a 

 spray of heath, an image of despair over its ravaged home." 



So far Darwin. But while he only gives a general 

 picture Forel here also relates many detailed observations of 

 the most interesting kind. He observed the expeditions of 

 the sanguinea to steal pupa? in Switzerland (Waadtland) from 

 the micldle of June to the middle of August. They march 

 in small troops which, in case of need, summon reinforce- 

 ments and therefore, as a mle, only reach their goal slowly. 

 Between the individual troops messengers or scouts run con- 

 tinually backwards and forwards. The first troop which 

 arrives at the hostile nest does not rush at it, as do the 

 Amazons, but contents itself with making provisional re- 

 connaissances, wherein some of the assailants are generally 

 made prisoners by the enemy, which have time to bethink 

 and to collect themselves. Reinforcements are now brought 

 up and a regular siege of the nest begins. A sudden 

 invasion, like that of the Amazons, is never seen. The 

 besieging army forms a complete ring round the hostile nest, 

 and the besiegers hold this with mandibles open and 



