Destructiveness of the Ants 59 
trees. It is on the outskirts of the forest, or around clear- 
ings, or near wide roads that let in the sun, that these formi- 
carlums are generally found. Numerous round tunnels, 
varying from half an inch to seven or eight inches in diameter, 
lead down through the mounds of earth; and many more 
from some distance around, also lead underneath them. At 
some of the holes on the mounds ants will be seen busily at 
work, bringing up little pellets of earth from below, and 
casting them down on the ever-increasing mound, so that 
its surface is nearly always fresh and new-looking. 
Standing near the mounds, one sees from every point of 
the compass ant-paths leading to them, all thronged with the 
busy workers carrying their leafy burdens. As far as the 
eye can distinguish their tiny forms, troops upon troops of 
leaves are moving up towards the central point, and disap- 
pearing down the numerous tunnelled passages. The out- 
going, empty-handed hosts are partly concealed amongst the 
bulky burdens of the incomers, and can only be distinguished 
by looking closely amongst them. The ceaseless, toiling 
hosts impress one with their power, and one asks—What 
forests can stand before such invaders? How is it that 
vegetation is not eaten off the face of the earth? Surely 
nowhere but in the tropics, where the recuperative powers 
of nature are immense and ever active, could such devasta- 
tion be withstood. 
Further acquaintance with the subject will teach the in- 
quirer that, just as many insects are preserved by being dis- 
tasteful to insectivorous birds, so very many of the forest 
trees are protected from the ravages of the ants by their 
leaves either being distasteful to them, or unfitted for the 
purpose for which they are required, whilst some have special 
means of defence against their attacks. None of the in- 
digenous trees appear so suitable for them as the introduced 
ones. Through long ages the trees and the ants of tropical 
America have been modified together. Varieties of plants 
that arose unsuitable for the ants have had an immense 
advantage over others that were more suitable; and thus 
through time every indigenous tree that has survived in the 
great struggle has done so because it has had originally, or 
has acquired, some protection against the great destroyer. 
The leaf-cutting ants are confined to tropical America; and 
