This larger fly was the one chosen for the first inspection, which was of the intensest. I permitted one to alight on my flannel pyjamas, which I wore while en deshabille in camp. No sooner had he alighted than his posterior was raised, his head lowered, and his weapons, consisting of four hair-like styles, unsheathed from the proboscis-like bag which concealed them, and immediately I felt pain like that caused by a dexterous lancet-cut or the probe of a fine needle. I permitted him to gorge himself, though my patience and naturalistic interest were sorely tried. I saw his abdominal parts distend with the plenitude of the repast until it had swollen to three times its former shrunken girth, when he flew away of his own accord laden with blood. On rolling up my flannel pyjamas to see the fountain whence the fly had drawn the fluid, I discovered it to be a little above the left knee, by a crimson bead resting over the incision. After wiping the blood the wound was similar to that caused by a deep thrust of a fine needle, but all pain had vanished with the departure of the fly. Having caught a specimen of this fly, I next proceeded to institute a comparison between it and the tsetse, as described by Dr. Livingstone on pp. 56-57, 'Missionary Travels and Researches in South Africa' (Murray's edition of 1868). The points of disagreement are many, and such as to make it entirely improbable that this fly is the true tsetse, though my men unanimously stated that its bite was fatal to horses as well as to donkeys. A descriptive abstract of the tsetse would read thus: "Not much larger than a common house-fly, nearly of the same brown colour as the honey-bee. After-part of the body has yellow bars across it. It has a peculiar buzz, and its bite is death to the horse, ox, and dog. On man the bite has no effect, neither has it on wild animals. When allowed to feed on the hand, it inserts the middle prong of three portions into which the proboscis divides, it then draws the prong out a little way, and it assumes a crimson colour as the mandibles come into brisk operation; a slight itching irritation follows the bite."