BITING FLIES


Of the many plagues that beset this land of Africa not the least are the
biting flies. Just as every tree and bush has thorns, so every fly has a
sting. Some bite by day only, some by night, and others at all times.
Even the ants have wings, and drop them in our soup as they resume their
plantigrade existence once again.

The worst biter that we have met in the many "fly-belts" that lie along
the Northern Railway is the tsetse fly: especially was he to be found at
a place called Same, and during the long trek from German Bridge on the
Northern Railway to Morogoro in the south. At one place there is a belt
thirty miles wide, and our progress was perpetual torture, unless we
passed that way at night. For the _Glossina morsitans_ sleeps by night
beneath leaves in the bush, and only wakes when disturbed. For this
reason we drive our horses, mules, and cattle by night through these
fly-belts. Savage and pertinacious to a degree are these pests, and
their bite is like the piercing of a red-hot needle. Simple and innocent
they appear, not unlike a house fly, but larger and with the tips of
their wings crossed and folded at the end like a swallow's. They are
mottled grey in colour, and their proboscis sticks out straight in
front. Hit them and they fall off, only to rise again and attack once
more; for their bodies are so tough and resistant, that great force is
required to destroy them. They are infected with trypanosomes, a kind of
attenuated worm that circulates in the blood, but fortunately not the
variety that causes sleeping sickness. At least we believe not. In any
case we shall not know for eighteen months, for that is usually the
latent period of sleeping sickness in man. Their bite is very poisonous,
and frequently produces the most painful sores and abscesses. But if