The precise part in the life of the community which is played by these great worker-majors, with the relation which it no doubt bears to their superior size and modified shape, has long been a puzzle to naturalists. The first idea was that they formed a soldier caste—a natural supposition in view of their great armour-plated heads, and elongated twisted jaws. Observation, however, does not bear out this theory. The jaws, in spite of their size, are not so well adapted for seizing on a plane surface—the skin, for instance, of an animal—as are those of the smaller workers; and, moreover, these large ants seemed to Mr. Bates to be less pugnacious than the others. “The position,” he tells us, “of the large-headed individuals in the marching column was rather curious. There was one of these extraordinary fellows to about a score of the smaller class; none of them carried anything in their mouths, but all trotted along empty-handed and outside the column, at pretty regular intervals from each other, like subaltern officers in a marching regiment of soldiers. I did not see them change their position, or take any notice of their small-headed comrades marching in the column, and when I disturbed the line, they did not prance forth or show fight so eagerly as the others.” Mr. Bates then hazards a conjecture that these big ants may serve indirectly to preserve the community, by being indigestible to birds, and that their great, twisted mandibles may be effective, whilst lying in the crops or stomachs of the latter. This seems possible, since a certain number of unpalatable individuals in a community of ants might make birds disinclined to eat any of them. I think, myself, however, that it is premature to speculate on the part in life which these curiously modified worker ants may be designed to play, until we know something more of their home economy, and particularly of their architecture. This, it is true, is of a very rude kind, nor do these marauding ants appear to have any permanent place of abode. Still, they may do something in the shape of building, and the peculiar jaws of the worker-major class suggest that they are formed for seizing some special object, or performing some special kind of labour.