ey 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
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. Now I was curious to ascertain whether F. sanguinea could
distinguish the pupae of F. fusca, which they habitually make into
slaves, from those of the little and furious F. flava, which they rarely
captur