1910. | as Carriers of Trypanosoma pecorum. 351 
This part of the investigation made two facts clear to the Commission. 
Firstly, that experiments to ascertain a carrier of any of the trypanosome 
diseases of domestic animals in Africa must necessarily be both prolonged 
and difficult. Secondly, that the distribution of the different species of 
biting flies in any country cannot be mapped out by a travelling entomologist. 
Accurate maps can only be made by the whole-hearted co-operation of those 
officials and settlers who are resident in the country for long periods. The 
observations should, where possible, be made daily, and continued for at 
least one year in the same locality. 
2. A StTupY OF THE NATURAL HISTORY OF THE BITING FLIES FOUND IN THE 
NEIGHBOURHOOD OF MPUMU. 
It should be clearly understood that whatever observations are given below 
refer to the natural history of these flies as observed in this locality only. 
Elsewhere difference in climatic and other conditions may give rise to 
variations in the habits and life-history of these flies. 
Glossina palpalis. 
The habits of the Glossina in this neighbourhood do not vary from the 
samme species on the Lake-shore. [heir presence was, however, both 
interesting and disquieting, as the Kasala stream, where they were captured, 
is at least 6 miles from the nearest point of Lake Victoria. Further, the 
stream has no connection whatever with this Lake. Rising in a narrow 
belt of forest at the foot of Mpumu hill, it flows through forest along the 
north-west face of the hill and then joins the Sezibwa River, which trends 
northwards, running parallel with the Nile, to empty into Lake Chioga. 
The Glossina were very scarce, three or four only being caught monthly 
between January and July, 1910. They were all caught at one spot—a ford 
of the stream, situated a mile or so from the laboratory. No tsetse-flies 
were seen in any other part of the stream. It is possible these flies had 
found their way down from the hill, since it was by no means an uncommon 
circumstance for some flies to escape from their cages when brought up by 
the fly-boys. Escaped flies were found on several occasions on different parts 
of the hill. 
The Tabanide. 
Habitat—Narrow belts of dense tropical forest, which commonly mark 
the windings of a flowing stream. The two essential factors appear to be 
deep shade and water, not necessarily running water. These flies are not 
found on grass-covered hill-tops. 
