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 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 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.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 the tyrants, who perhaps fancied that, after all, they had been victorious in their late combat.
At the same time I laid on the same place a small parcel of the pupae of another species, F.flava, with a few of these little yellow ants still clinging to the fragments of their nest.

This species is sometimes, though rarely, made into slaves, as has been described by Mr.Smith.
Although so small a species, it is very courageous, and I have seen it ferociously attack other ants.

In one instance I found to 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 neighbours with surprising courage.