various gradations to insignificance, if not extinction, are known
by naturalists to occur in numerous genera; and so far they have
only been explained on the supposition of the descent of the
different species from a common progenitor.

(PLATE 3. HEADS OF MOT-MOTS.)

As I returned to the boat, I crossed a column of the army or
foraging ants, many of them dragging along the legs and mangled
bodies of insects that they had captured in their foray. I
afterwards often encountered these ants in the forests and it may
be convenient to place together all the facts I learnt respecting
them.

ECITONS, OR FORAGING ANTS.

The Ecitons, or foraging ants, are very numerous throughout Central
America. Whilst the leaf-cutting ants are entirely vegetable
feeders, the foraging ants are hunters, and live solely on insects
or other prey; and it is a curious analogy that, like the hunting
races of mankind, they have to change their hunting-grounds when
one is exhausted, and move on to another. In Nicaragua they are
generally called "Army Ants." One of the smaller species (Eciton
predator) used occasionally to visit our house, swarm over the
floors and walls, searching every cranny, and driving out the
cockroaches and spiders, many of which were caught, pulled or
bitten to pieces, and carried off. The individuals of this species
are of various sizes; the smallest measuring one and a quarter
lines, and the largest three lines, or a quarter of an inch.