to escape by their own efforts, and to assist whom there is no time, and possibly but little inclination. But in spite of such catastrophes, and of the danger and inconvenience which these driver-ants cause to the negroes, they are yet, in reality, very useful to them, since, several times a year, their huts are freed from the vermin with which they at all times abound. If the gorilla and elephant fly before these ants, one can understand that snakes, however large, would also be afraid of them; and accordingly we have a curious story told by the natives, of the anxiety felt by the great python lest he should be overtaken by their armies, whilst lying torpid after a meal, and of the means which he takes to avoid such a catastrophe. Having killed his prey by crushing it in the great folds of his body, he leaves it lying on the ground, and does not return until, having made a circle of a mile or more in diameter, about the body, he is assured that no ant-army is on the march. Only then does he dare to swallow his prey and risk the dangerous period of sluggish inactivity which is necessitated by the process of digestion. If, however, the object of fear should be met with the python glides off with all possible speed, leaving the booty to be devoured by the ants should they happen to come upon it. The habit of these driver-ants of making a tunnel as they march along, and thus sheltering themselves from the heat of the sun, is very remarkable, but I cannot quite understand how they drive it so deep under the ground as Du Chaillu says. To do so must surely delay them for a very long time, and the quicker and more expedient course would seem to be to wait for the sun to go down, and then to cross the open space. However, we should never assume, in natural history, that a certain course will be pursued by any animal, simply because it is the best one. Often, however obvious this seems, they act otherwise. From other accounts, however, it would seem as if the ants threw up their tunnel on the surface of the ground instead of excavating beneath it, and that, sometimes, the structure reared by them is more of the nature of an awning than a tunnel. The Rev. Dr. Savage, for instance, says: “If they should be detained abroad till late in the morning of a sunny day, by the quantity of their prey, they will construct arches over their path, of dirt agglutinated by a fluid excreted from their mouth. If their way should run under thick grass, sticks, etc., affording sufficient shelter, the arch is dispensed with; if not, so much dirt is added as is necessary to eke out the arch, in connexion with them.”