A person, on first entering a tropical forest, is astonished at the labours of the ants: well-beaten paths branch off in every direction, on which an army of never-failing foragers may be seen, some going forth, and others returning, burdened with pieces of green leaf, often larger than their own bodies.
A small dark-coloured ant sometimes migrates in countless numbers.
One day, at Bahia, my attention was drawn by observing many spiders, cockroaches, and other insects, and some lizards, rushing in the greatest agitation across a bare piece of ground.

A little way behind, every stalk and leaf was blackened by a small ant.

The swarm having crossed the bare space, divided itself, and descended an old wall.

By this means many insects were fairly enclosed; and the efforts which the poor little creatures made to extricate themselves from such a death were wonderful.

When the ants came to the road they changed their course, and in narrow files reascended the wall.