The common house-fly was a terrible pest at all times. They swarmed over everything, and were a particular source of annoyance when food was being prepared, or being eaten. It was impossible to take steps to reduce their number in the limitless areas through which we were constantly passing, and there was nothing for it but to endure the plague, while, whenever camp was established for a few days, all rubbish was scrupulously burned or buried so that they would have as little to attract them to our neighbourhood as possible. A large glossy “blue-bottle”—following the ghastly trail of dying transport animals, was also a common and disease-carrying pest. When the elephants—mentioned previously—were shot in the Ulugúru Mountains, they were miles from any habitation, and in vague bush country, which one would judge was no habitat of “blue-bottles,” yet in an hour they were in millions on the dead carcases—so many that the standing grass was weighed down with the blackness of flies settled on each stem. The sense that brought such swarms to one small centre in so short a time is beyond understanding. Should a horse die on the roadside, but a day will elapse before it becomes a seething mass of “blue-bottle” larva and terrible to look upon. Mosquitoes, in regard to their irritating bite and their nocturnal activities, were, on the whole, not very troublesome, and in no instance have I a record of their being particularly bad, but they carry the malaria germ, and, in that they did so, they were our most deadly enemy. As protection against them everyone was supposed, by S.M.O. order, to sleep beneath mosquito net, but that was often quite impossible when trekking, and our kit miles in rear. In some parts we passed through, especially if riding, the tsetse fly was a terrible pest, for they bite hard and deep, and follow you persistently on your way for many miles. It is that fly which is credited with carrying the germ of that dread disease sleeping sickness—while, as is well known, its bite is particularly fatal to imported horses and mules, and, in lesser degree, to cattle. [Sidenote: ANTS AND BEES]