h long. But the most
prominent, by their immense numbers, are the dreaded sauebas. Well-beaten
paths branch off in every direction through the forest, on which broad
columns may be seen marching to and fro, each bearing vertically a
circular piece of leaf. Unfortunately they prefer cultivated trees,
especially the coffee and orange. They are also given to plundering
provisions; in a single night they will carry off bushels of farina.
They are of a light red color, with powerful jaws. In every formicarium
or ant colony there are three sets of individuals--males, females, and
workers; but the sauebas have the singularity of possessing three classes
of workers. The light-colored mounds often met in the forest, sometimes
measuring forty feet in diameter by two feet in height, are the domes
which overlie the entrances to the vast subterranean galleries of the
saueba ants. These ants are eaten by the Rio Negro Indians, and esteemed
a luxury; while the Tapajos tribes use them to season their mandioca
sauce. Akin to the vegetable-feeding sauebas are the carnivorous ecitons,
or foraging ants, of which Bates found ten distinct species. They hunt
for prey in large organized armies, almost every species having its own
special manner of marching and hunting. Fortunately the ecitons choose
the thickest part of the forest. The fire-ant is the great plague on the
Tapajos. It is small, and of a shiny reddish color; but its sting is
very painful, and it disputes every fragment of food with the
inhabitants. All eatables and hammocks have to be hung by cords smeared
with copaiba balsam.

[Footnote 173: Amazonia is divided into four distinct zoological
districts: those of Ecuador, Peru, Guiana, and Brazil; the limits being
the Amazon, Madeira, and Negro. The species found on one side of these
rivers are seldom found on the other.]

The traveler on the Amazon frequently meets with conical hillocks of
compact earth, from three to five feet high, from which radiate narrow
covered galleries or arcades. The architects of these wonderful
structures are the termites, or "white ants," so called, though they
belong to a higher order of insects, widely differing from the true
ants. The only thing in common is the principle of division of labor.
The termite neuters are subdivided into two classes, soldiers and
workers, both wingless and blind. Their great enemy is the ant-eater;
but it is a singular fact, noticed by Bates, that the soldiers only
att