Chap. viii. Slave-making Instinct. 217 



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 existence of so extraordinary an 

 instinct as that of making slaves. Hence, I will give the observa- 

 tions which I 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 black and not above half the size 

 of their red masters, so that the contrast in their appearance is 

 great. When the nest is slightly disturbed, the slaves occasionally 

 come out, and like their masters are much agitated and defend the 

 nest : when the nest is much disturbed, and the lame and pupa? 

 are exposed, the slaves work energetically together with their 

 masters in carrying them away to a place of safety. Hence, it is 

 clear, that the slaves feel quite at home. During the months of 

 June and July, on three successive years, I watched for many hours 

 several nests in Surrey and Sussex, and never saw a slave either 

 leave or enter a nest. As, during these months, the slaves are very 

 few in number, I thought that they might behave differently when 

 more numerous ; but Mr. Smith informs me that he has watched 

 the nests at various hours during May, June, and August, both in 

 Surrey and Hampshire, and has never seen the slaves, though 

 present in large numbers in August, either leave or enter the nest. 

 Hence he considers them as strictly household slaves. The masters, 

 on the other hand, may be constantly seen bringing in materials for 

 the nest, and food of all kinds. During the year 1860, however, 

 in the month of July, I came across a community with an unusually 

 large stock of slaves, and I observed a few slaves mingled with 

 their masters leaving the nest, and marching along the same road 

 to a tall Scotch-fir-tree, twenty-five yards distant, which they 

 ascended together, probably in search of aphides or cocci. According 

 to Huber, who had ample opportunities for observation, the slaves 

 in Switzerland habitually work with their masters in. making the 

 nest,^ and they alone open and close the doors in the morning and 

 evening; and, as Huber expressly states, their principal office is 

 to search for aphides. This difference in the usual habits of the 

 masters and slaves in the two countries, probably depends merely 



