SPECIES OF ANTS. 79 
larvie as food. It is as if we had small dwarfs, about 
eighteen inches to two feet long, harbouring in the 
. walls of our houses, and every now and then carrying 
off some of our children into their horrid dens. 
Most ants, indeed, will carry off the larve and pup 
of others if they get a chance; and this explains, or at 
any rate throws some light upon, that most remarkable 
phenomenon, the existence of slavery among ants. If 
you place a number of larve and pupe in front of a 
nest of the Horse ant (Ff. rufa), for instance, they are 
soon carried off; and those which are not immediately 
required for food remain alive for some time, and are 
even fed by their captors. 
Both the Horse ant (Mormica rufa, Pl. II. fig. 5) 
and the slave ant (Ff. fusca, Pl. I. fig. 3) are abun- 
dant species, and it must not unfrequently occur 
that the former, being pressed for food, attack the 
latter and carry off some of their larvae and pupe. 
Under these circumstances it no doubt occasionally 
happens that the pupze come to maturity inthe nests 
of the Horse ant, and it is said that nests are some- 
times, though rarely, found in which, with the legiti- 
mate owners, there are a few F. fuscas. With the 
Horse ant this is, however, a very rare and exceptional 
phenomenon ; but with an allied species, F. sanguinea 
(Pl. I. fig. 6), a species which exists in some of our 
southern counties and throughout Europe, it has be- 
come an established habit. The F. sanguineas make 
periodical expeditions, attack neighbouring nests, and 
