Earnestly as I wished to hurry on to Unyanyembe, still a heart-felt anxiety about the arrival of my goods carried by the fourth caravan, served as a drag upon me and before my caravan had marched nine miles my anxiety had risen to the highest pitch, and caused me to order a camp there and then.  The place selected for it was near a long straggling sluice, having an abundance of water during the rainy season, draining as it does two extensive slopes.  No sooner had we pitched our camp, built a boma of thorny acacia, and other tree branches, by stacking them round our camp, and driven our animals to grass; than we were made aware of the formidable number and variety of the insect tribe, which for a time was another source of anxiety, until a diligent examination of the several species dispelled it.

As it was a most interesting hunt which I instituted for the several specimens of the insects, I here append the record of it for what it is worth.  My object in obtaining these specimens was to determine whether the genus Glossina morsitans of the naturalist, or the tsetse (sometimes called setse) of Livingstone, Vardon, and Gumming, said to be deadly to horses, was amongst them.  Up to this date I had been nearly two months in East Africa, and had as yet seen no tsetse; and my horses, instead of becoming emaciated—­for such is one of the symptoms of a tsetse bite—­had considerably improved in condition.  There were three different species of flies which sought shelter in my tent, which, unitedly, kept up a continual chorus of sounds—­one performed the basso profondo, another a tenor, and the third a weak contralto.  The first emanated from a voracious and fierce fly, an inch long, having a ventral capacity for blood quite astonishing.

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.