ZOOLOGY 
377 
House-flies, except in some of the Arab towns and large European settle¬ 
ments or in places where much cattle are kept, are not nearly so severe a pest 
as in South Africa or the Mediterranean countries. Indeed, in cool places like 
Zomba the domestic fly does not give as much trouble as in many country 
houses in England. 
And now we come to the tsetse, perhaps the most serious of all the many 
insect pests of Africa in its check to European enterprise. It is difficult to 
overestimate the importance of the part played by this noxious little insect 
in preventing the opening up of Central Africa. 
This was first experienced by the earlier Portuguese Expeditions of five 
hundred or six hundred mounted men which would set out from Sena on the 
Lower Zambezi in the 16th and 17th centuries to secure the gold mines to 
the north and south. We read in Portuguese records how their horses soon 
succumbed to the attacks of a fly. The riders were left without steeds and the 
expeditions came to an abortive termination, many of the Europeans dying 
of fever or succumbing to the attacks of the natives through having to make 
their way on foot. But for the tsetse-fly the whole history of South-Central 
Africa would be different. It would have been rapidly traversed by mounted 
men, not nearly so much ill-health would have pursued explorers and pioneers 
forced to travel on foot, and the whole question of transport would be rendered 
infinitely more easy as coaches and waggons could run and huge numbers 
of pack animals—horses, mules and oxen—might convey goods which at 
present are carried on men’s heads. Undoubtedly the tsetse-fly has checked 
the southward range of Muhammadan raiders from the north. But for the 
presence of this insect in the Congo Basin and in Equatorial East Africa, the 
Muhammadanised negroes and Arabs of the Sudan would have spread much 
farther south than they have done already on their sturdy little ponies. 
The tsetse is a most insignificant fly in appearance. I give here drawings 
of it that I have done from specimens sent to the British Museum. I have 
purposely drawn these myself because the conscientious entomologist will 
persist in presenting to the public in illustrated natural history works and 
books of travel a tsetse-fly which the average traveller finds it quite impossible 
to recognise in Africa, about three times the size of the largest bluebottle 
and with wings spread at right angles to the body. 1 
When I first went to Tropical Africa I looked in vain for a gigantic blue¬ 
bottle with vivid black and white striping, and a proboscis half an inch long: 
it was a long time before it occurred to me that a small brownish fly with a 
faintly barred brown and white abdomen (which again was generally concealed 
by the closely-folded wings) could be the tsetse, though I knew it was a fly 
capable of inflicting a disagreeable prick on my skin and not infrequently 
drawing from me a drop of blood. This, however, is the appearance of the 
true tsetse (Glossina morsitans),. and the drawing which I give here very fairly 
represents its ordinary appearance with the wings closely folded over the back. 
The actual fly is a little smaller than the size represented in the drawing. 
Fortunately the tsetse-fly is not present in all parts of British Central 
Africa. Roughly speaking, it may be said that it is absent from any district 
that is above 3000 feet in altitude and is not found in many of the low- 
lying lands for some hitherto unexplained reason, no doubt connected with 
human settlement. It is present throughout the whole valley of the great 
1 This figure is familiar to most persons in Livingstone’s first book of travels. It has been repeated 
and repeated in succeeding books. 
