The Saüba ants of tropical America carry their agricultural operations a step further. Dwelling in underground nests, they sally forth upon the trees, and cut out of the leaves large round pieces, about as big as a shilling. These pieces they drop upon the ground, where another detachment is in waiting to convey them to the galleries of the nest. There they store enormous quantities of these round pieces, which they allow to decay in the dark, so as to form a sort of miniature mushroom bed. On the mouldering vegetable heap they have thus piled up, they induce a fungus to grow, and with this fungus they feed their young grubs during their helpless infancy. Mr. Belt, the “Naturalist in Nicaragua,” found that native trees suffered far less from their depredations than imported ones. The ants hardly touched the local forests, but they stripped young plantations of orange, coffee, and mango trees stark naked. He ingeniously accounts for this curious fact by supposing that an internecine struggle has long been going on in the countries inhabited by the Saübas between the ants and the forest trees. Those trees that best resisted the ants, owing either to some unpleasant taste or to hardness of foliage have in the long run survived destruction; but those which were suited for the purpose of the ants have been reduced to nonentity, while the ants in turn were getting slowly adapted to attack other trees. In this way almost all the native trees have at last acquired some special means of protection against the ravages of the leaf-cutters; so that they immediately fall upon all imported and unprotected kinds as their natural prey. This ingenious and wholly satisfactory explanation must of course go far to console the Brazilian planters for the frequent loss of their orange and coffee crops. Mr. Alfred Russel Wallace, the co-discoverer of the Darwinian theory (whose honors he waived with rare generosity in favor of the older and more distinguished naturalist), tells a curious story about the predatory habits of these same Saübas. On one occasion, when he was wandering about in search of specimens on the Rio Negro, he bought a peck of rice, which was tied up, Indian fashion, in the local bandanna of the happy plantation slave. At night he left his rice incautiously on the bench of the hut where he was sleeping; and next morning the Saübas had riddled the handkerchief like a sieve, and carried away a gallon of the grain for their own felonious purposes. The underground galleries which they dig can often be traced for hundreds of yards; and Mr. Hamlet Clark even asserts that in one case they have tunnelled under the bed of a river where it is a quarter of a mile wide. This beats Brunel on his own ground into the proverbial cocked hat, both for depth and distance.