CHAP. VIII.] SLAVE-MAKING INSTINCT. 203 



the size of their red masters, so that the contrast in their appear- 

 ance 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 

 larvae and pupae 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 mimerous ; 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 oppor- 

 tunities 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 on the slaves being captured 

 in greater numbers in Switzerland than in England. 



One day I fortunately witnessed a migration of F. sanguinea 

 from one nest to another, and it was a most interesting spectacle 

 to behold the masters carefully carrying their slaves in their jaws 

 instead of being carried by them, as in the case of F. rufescens. 

 Another day my attention was struck by about a score of the slave- 

 makers haunting the same spot, and evidently not in search of 

 food ; they approached and were vigorously repulsed by an inde- 

 pendent community of the slave-species (F. fusca) ; sometimes as 

 many as three of these ants clinging to the legs of the slave-making 

 F. sanguinea. The latter ruthlessly killed their small opponents, 

 and carried their dead bodies as food to their nest, twenty-nine 

 yards distant; but they were prevented from getting any pupae to 

 rear as slaves. I then dug up a small parcel of the pupae of F. 

 fusca from another nest, and put them down on a bare spot near 

 the place of combat ; they were eagerly seized and carried off by 



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