Of the numerous true ants which exist in all parts of Tropical America,
the sauba is one of the most remarkable. In all parts of the country--
as well near the abodes of man as in the distant wilds--large mounds are
seen, two feet in length, and often upwards of forty yards in
circumference, and distinguished from the surrounding soil by the
difference of colour. Yet these mounds are merely the domes or upper
works of the vast subterranean galleries which run for enormous
distances and to great depths below the surface. Unlike the termites,
the armies go forth in open daylight in vast hordes, to obtain food or
materials for the construction of their wonderful habitations.
Sometimes, many hundred yards away from these mounds, the whole ground
seems covered with animated leaves, each of the size of a sixpence,
moving at a steady pace over the ground. Each leaf is held vertically
in the mandibles of an ant, which is conveying it for the purpose of
thatching the domes which cover the entrance to its subterranean abode;
the roof thus formed protecting the cells beneath, rilled with young,
from the heavy rains. Going in the direction whence the army is seen
coming, we may find a tree covered by innumerable multitudes employed in
cutting off leaves. Here the labourers are protected by the warrior
class, who appear also to perform the duties of overlookers, and keep
them to their tasks. Each ant, on gaining a leaf, commences with its
scissor-like jaws to make a semicircular incision on the upper side. It
then takes it into its jaws, and detaches it by a sharp jerk. Having
done this, it descends to the ground, and joining its comrades, who have
been similarly employed, they return with their loads to the colony.
Frequently, however, while an ant is up the tree, the piece of leaf
falls to the ground, when it sets to work to cut off another; while
fresh labourers appear, to carry away the pieces which have thus
accumulated.
The sauba ants are greatly dreaded by the inhabitants, as they
frequently attack their coffee and orange-trees, and utterly destroy
them. Sometimes, indeed, plantations have to be abandoned in
consequence of the inroads of these persevering insects.
The body of the sauba ant is of a pale reddish-brown colour, and of a
solid consistency. 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 on the sides of
their head. The other workers do not possess this peculiar frontal eye,
nor is it found in any other species of ant.
It is wonderful what extensive tunnels these ants will form. Near Rio
de Janeiro a tunnel was discovered, excavated by the creatures under the
River Parahiba, as broad as the Thames at London Bridge. Near Para
they, on one occasion, pierced the embankment of a large reservoir to
such an extent as to allow the escape of a vast body of water before the
damage could be repaired. In the same neighbourhood an attempt was made
to destroy their colonies, by blowing fumes of sulphur down the
galleries by means of bellows. Mr Bates relates, that he saw smoke
issuing from a vast number of outlets, one of which was seventy yards
distant from the place where the bellows were used.
They wander to a great distance in search of plunder, and enter houses
for the purpose of carrying off the farina or mandioca meal. The same
naturalist relates that he was one night awoke by his servant telling
him that rats were robbing the farina baskets. On listening, he was
certain that the noise was unlike that made by rats. On going to the
storeroom he there found a broad column of sauba ants, consisting of
thousands of individuals, passing to and fro between the door and his
baskets of meal. Most of those passing outwards were loaded each with a
grain of farina, larger and many times heavier than the bodies of the
carriers. The baskets, which were on a high table, were entirely
covered with ants, many hundreds of whom were employed in snipping the
dry leaves which served as a lining; and this had produced the rustling
sound which had disturbed him. He and his servant in vain attempted to
exterminate them by killing them with their wooden clogs. Fresh hosts
came on to take the place of the slain. The next night they returned,
when he attempted to get rid of them by laying trains of gunpowder along
their line to blow them up. Not, however, till he had repeated this
operation several times, did the survivors of the daring depredators
retreat.