re provided for them
to commence housekeeping with; and cups of nectar and luscious fruits
await them every day. But there is a reverse to the picture. In the dry
season on the plains, the acacias cease to grow. No young leaves are
produced, and the old glands do not secrete honey. Then want and hunger
overtake the ants that have reveled in luxury all the wet season; many
of the thorns are depopulated, and only a few ants live through the
season of scarcity. As soon, however, as the first rains set in, the
trees throw out numerous vigorous shoots, and the ants multiply again
with astonishing rapidity.

Both in Brazil and in Nicaragua I paid much attention to the relation
between the presence of honey-secreting glands on plants, and the
protection the latter secured by the attendance of ants attracted by the
honey. I found many plants so protected; the glands being specially
developed on the young leaves, and on the sepals of the flowers. Besides
the bull's-horn acacias, I, however, only met with two other genera of
plants that furnished the ants with houses, namely, the trumpet tree
and some of the evergreen shrubs; but I have no doubt that there are
many others. The stem of the Cecropia, or trumpet tree, is hollow, and
divided into cells by partitions that extend across the interior of the
hollow trunk. The ants gain access by making a hole from the outside,
and then burrow through the partitions, thus getting the run of the
whole stem. They do not obtain their food directly from the tree, but
keep brown scale insects in the cells, which suck the juices from the
tree, and secrete a honey-like fluid that exudes from a pore on the
back, and is lapped up by the ants. In one cell eggs will be found, in
another grubs, and in a third pupae, all lying loosely. In another cell,
by itself, a queen ant will be found, surrounded by walls made of a
brown waxy-looking substance, along with about a dozen scale insects to
supply her with food. I suppose the eggs are removed as soon as laid,
for I never found any along with the queen ant. If the tree be shaken,
the ants rush out in myriads, and search about for the molester. This
case is not like the last one, where the tree has provided food and
shelter for the ants, but rather one where the ant has taken possession
of the tree, and brought with it the scale insects; but I believe that
its presence must be beneficial. I have cut into some dozens of the
trumpet trees, and never could