S(y6 THE ORIGIN OP SPECIES 



uiul Iliimpslure, and has never seen the shives, though 

 present in hirge numbers in August, either leave or enter 

 the nest. Hence he considers them as strictly iiousehold 

 slaves. The masters, on the other hand, may be con- 

 stantly 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 un- 

 usually large stock of slaves, and I observed a few slaves 

 mingled with their masters leaving the nest, and march- 

 ing along the same road to a tall Scotch firtree, twenty- 

 five yards distant, which they ascended together, prob- 

 ably 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 on 

 the slaves being captured in greater numbers in Switzer- 

 land 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 car- 

 rying 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 re- 

 pulsed by an independent 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. 



