INSTINCT 197 



father. This ant is absolutely dependent on its slaves ; 

 without their aid, the species would certainly be- 

 come extinct in a single year. The males and fertile 

 females do no work. The workers or sterile females, 

 though most energetic and courageous in capturing 

 slaves, do no other work. They are incapable of making 

 their own nests, or of feeding their own larvae. When 

 the old nest is found inconvenient, and they have to 

 migrate, it is the slaves which determine the migration, 

 and actually carry their masters in their jaws. So 

 utterly helpless are the masters, that when Huber shut 

 up thirty of them without a slave, but with plenty of 

 the food which they like best and with their larvsB and 

 pupae to stimulate them to work, they did nothing ; they 

 could not even feed themselves, and many perished of 

 hunger. Huber then introduced a single slave (F. 

 fusca), and she instantly set to work, fed and saved the 

 survivors ; made some cells and tended the larvae, and 

 put all to rights. What can be more extraordinary 

 than these well-ascertained facts ? If we had not 

 known of any other slave-making ant, it would have 

 been hopeless to have speculated how so wonderful an 

 instinct could have been perfected. 



Another species, Formica sanguinea, was likewise 

 first discovered by P. Huber to be a slave-making ant. 

 This species is found in the southern parts of England, 

 and its habits have been attended to by Mr. F. Smith, 

 of the British Museum, to whom I am much indebted 

 for information on this and other subjects. Although 

 fully trusting to the statements of Huber and Mr. 

 Smith, I tried to approach the subject in a sceptical 

 frame of mind, as any one may well be excused for 

 doubting the truth of so extraordinary and odious an 

 instinct as that of making slaves. Hence I will give 

 the observations which I have myself made, in some 

 little detail. I opened fourteen nests of F. sanguinea, 

 and found a few slaves in all. Males and fertile 

 females of the slave-species (F. fusca) are found only in 

 their own proper communities, and have never been 

 observed in the nests of F. sanguinea. The slaves are 



