6 3 
percentage of resident natives having enlarged cervical glands without 
apparent cause is indicated—Kalombe (i; per cent.), Dibwe (t8 per 
cent.), Miambwe (; per cent.), Lokula (6 per cent.). 
A proportion of the infected persons probably contracted their disease elsewhere. 
These villages have a considerable immigrant population ; they supply many carrier'- 
and a large proportion of their people are continually absent, collecting rubber, in 
the forest near rivers where tsetse flies are said to exist. 
Had the flies been present in as large numbers as, for instance, at 
Kamimbi, it is quite inconceivable that the passage of even 300 men 
should have enticed them all away from their usual haunts. 
The occasional presence of G. palpalis in places at a considerable 
distance from any collection of water may perhaps be explained by 
their habit of following animals. 
In the Gambia, and again in the Congo, a single G. -palpalis (?) ha- been 
seen on a dry plateau a couple of hundred feet above and about a mile distant from 
the nearest stream. 
As would be surmised from what has already been said, Gloss inn 
palpalis is able to fly quickly and for comparatively long distances. 
They are said to occasionally fly into the railway carriages as they pass near 
Palabala in the Lower Congo. They are frequently seen on steamers or canoes in 
mid-river, and distant 300 to 500 yards from either bank. On entering a moving 
vehicle the flies seek sheltered spots, and it is under the sunshade of the canoe or in 
corners of a cabin sheltered from the wind that they take refuge. 
On one occasion in the Gambia a G. palpalis (?) persistently followed one of us 
(J. E. D.), who was riding rapidly on a bicycle, for several hundred yards. 
At Tshofa, G. palpalis was frequently seen on the verandah of our house, 
although it was placed on high ground and at least two hundred feet above the river, 
which was about half a mile away. 
Although G. palpalis has such extensive powers of flight, it seems 
to be very local in its habits. As has often been observed, not a 
single fly may be seen at 100 yards from a river although its banks 
swarm with them. 
At M’Swata, however, G. palpalis was regularly seen along a little-frequented 
path on high ground and in open park country at a distance of 500 yards 
from the water and of 250 yards from the edge of the fringe of brush bordering the 
river. In partial explanation it should be stated that there was a good deal of game 
in the neighbourhood. 
It has been often noticed that G. palpalis is most numerous at, 
and seems to lie in wait by, fords or frequented paths. Its habits 
have seemed to be more or less regular. 
On one occasion, while resting by the side of a path, a G. palpalis was noticed to 
return on three occasions to the same spot on the sheltered under surface of a gra" 
stalk after having been driven off by a native porter whom it was trying to bite. 
Tsetse flies were practically never seen during rain and wind. 
They were most conspicuous and seemed most vivacious on bright. 
