The head is armed with a pair of sharp spines, while
the thorax has three pairs of the same character.

There appear to be three orders of workers among them, greatly differing
in size. One order has an enormously large head; the head of another is
very highly polished; while that of a third is opaque--to enable it,
apparently, to perform the duties of a subterranean labourer. The earth
of which the domes of the sauba ants are composed is brought up from a
considerable depth below. There are numerous entrances leading to the
galleries, but, under ordinary circumstances, they are kept closed. The
smaller galleries lead, at a depth of several feet, to a broad,
elaborately-worked tunnel of four or five inches in diameter, which
conducts downwards to the centre chamber; the abode of the royal pair,
on whom devolves--as is the case with the termites--the duty of
propagating the species. Here they are guarded much in the same way by
the labourers, who deposit the eggs in the cells, and finally assist in
the exit of the winged males and females--which fly forth to be
destroyed in vast numbers, the few who remain becoming the parents of
other families.

The female winged ants are of considerable size, measuring fully two and
a quarter inches across the wings. The male is very much smaller.

The royal chamber is curiously constructed. As soon as the newly-wedded
pair are conducted within, the workers, who are themselves much smaller,
so diminish the size of the entrance that it is impossible for the king
and queen to escape. Round it are numerous exits and entrances, through
which the workers convey the eggs when laid. The queen, after the death
of her consort, lives for two or three years, employed during the whole
of the time in laying eggs, at the rate of fifty in a minute. This will
give some idea of the rapid increase of the population.

The workers vary somewhat in size and appearance. While a large number
are employed in bringing in leaves and granules of earth for thatching
their domes, as well as various sorts of provision, others are engaged
in tending the royal chamber--carrying the eggs to the cells, and
watching over the young. There is another class, whose heads are
covered with hairs, and who appear to be employed entirely below ground,
probably as excavators or tunnellers.

Like the Cyclops, they have in the centre of their forehead a single
eye, very different in structure to the compound eyes