242 SPECIAL INSTINCTS. 



my surprise an independent community of F. flava under a 

 stone beneath a nest of the slave-making F. sanguinea ; and 

 when I had accidentally disturbed both nests, the little ants 

 attacked their big neighbors with surprising courage. Now 

 I was curious to ascertain whether F. sanguinea could dis- 

 tinguish the pupae 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 seize the pupae of F. fusca, whereas 

 they were much terrified when the}' came across the pupae, 

 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 

 pupae. I traced a long file of ants burdened with booty, 

 for about forty yards back, 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. 



Such are the facts, though they did not need confirma- 

 tion by me, in regard to the wonderful instinct of making 

 slaves. Let it be observed what a contrast the instinctive 

 habits of F. sanguinea present with those of the conti- 

 nental F. rufescens. The latter does not build its own 

 nest, does not determine its own migrations, does not col- 

 lect food for itself or its young, and cannot even feed 

 itself: it is absolutely dependent on its numerous slaves. 

 Formica sanguinea, on the other hand, possesses much 

 fewer slaves, and in the early part of the summer extremely 

 few : the masters determine when and where a new nest 

 shall be formed, and when they migrate, the masters carry 

 the slaves. Both in Switzerland and England the slaves 

 seem to have the exclusive care of the larvae, and the masters 

 alone go on slave-making expeditions. In Switzerland the 



