No one can pass through the upper or lower forests without noticing the much more prominent nests made in the trees by another insect, a small species of black ant. These nests are often as large as a football, and are apparently made of cow-dung, or earthy and vegetable matter, forming a coarse papery substance; they are peopled by large numbers of ants, and are dark brown in colour. If one is procured—not an easy matter, for the little inhabitants rush out and attack the intruder, and dig their jaws into one’s flesh in a way to make one jump—it will be seen, on cutting open the nest vertically, that there is a series of thin floors about half-an-inch apart and supported by pillars. The ants run about frantically, their chief care being to carry the white eggs and pupæ to a place of safety. But it will be observed that in the nest there are to be seen a number of very small but handsome beetles, perhaps in the proportion of one to a hundred of the ants. What purpose do these entirely different insects serve in the economy of ant life? It appears that this is a fact observed in the nests of many other kinds of ants, for the Rev. J. G. Wood, in his charming book, “Homes without Hands,” says that above thirty species of beetle are known as inhabiting ants’ nests. But he can throw no light upon the purpose served by the presence of the beetles. Besides these large and conspicuous nests, containing probably thousands of ants, other nests, of all sizes, from about that of a nut to an orange and upwards, may be seen: the hamlets, villages, and small towns of the ant world, while the large nests are the great cities of their commonwealth. The ants inhabiting these dwellings appear to be all of one species, and about three-sixteenths of an inch in length. What can these little creatures live upon?—for they can hardly descend for it to the ground, from heights of twenty, thirty, and even fifty or sixty, feet.