Page:Popular Science Monthly Volume 5.djvu/102

92 the hosts left his plants to attend to home-affairs, and the removal of dead ants, food, and undeveloped larvæ and pupæ from their dwellings to a new home, was carried on with extraordinary zeal. The old burrow was deserted, and their ravages for a time suppressed. Corrosive sublimate makes the ants mad and furious. A little of the powder was sprinkled in one of their paths; so soon as the ants touched it, they ran wildly about attacking others, and very soon compact masses, or balls of ants, would be found biting each other. Huge fellows from the formicaries, measuring three-quarters of an inch in length, came forth to set matters right, but on touching the poison their bravery forsook them. They attacked others, and were themselves attacked, and became the centres of balls of furious ants.

Many indigenous trees escape their ravages, evidently because distasteful. Through long ages the ants and trees of tropical America have become somewhat modified together. All plants disliked by ants have a great advantage over others, and thus a selection has gone on, in which introduced species do not share. The lime is less liked than the orange or the citron, and, while these are inevitably destroyed, unless protected, the lime would probably survive; and Mr. Belt judiciously remarks that a little more or less acridity, or a slight chemical difference in the composition of the tissues of a leaf, so small that it is inappreciable to our senses, may be sufficient to insure the preservation or the destruction of a species throughout an entire continent. The paths of these ants ramify in every direction from their abodes, and are more thronged than the streets of London. They seek the open spaces near margins of the forest, and excavate a series of galleries, which are the scene of manifold operations. Continually the workers bring in burdens consisting chiefly of fragments of leaves. Naturalists have differed as to the use to which these leaves are put. Some suppose they are used as food, others, to line their galleries; the explanation given by Mr. Belt is, that the leaves are used as a manure, on which grows a minute fungus, which is the food of the ants; that they are, in reality, mushroom growers and eaters. This extraordinary conclusion he arrived at by careful observations. He repeatedly explored their nests, which are a series of rounded chambers about as large as a man's head, connected by tunneled passages leading from one chamber to another. In the burrows the leaves could never be found in quantity; they were evidently directly used up; but the chambers were about three-fourths filled with a speckled-brown, spongy-looking mass. Throughout this were ants with pupæe and larvæ. Upon careful examination, it proved to be minutely subdivided leaves, brown and withered, overgrown and lightly connected by a minute, white fungus, that ramified in every direction through it. This fungus was found in every chamber opened, and in the midst of it ant-nurses and immature ants. When the nests were disturbed, this fungus, or ant-food, was guarded with great care, and every atom of it