RESEARCH IN BRITISH WEST AFRICA. 223 
Movement.—The notes given with regard to G. palpalis apply equally well to 
this species, as also do those on range of flight and on clothing. 
Effect of Sun.—This species is not so susceptible to the sun’s rays as is 
G, palpalis. 
Daily Prevalence—I had not the same opportunity of studying this point in 
the Gambia, never having remained very long in a morsitans-area, but from 
observations elsewhere and scattered records in the Gambia, I am of opinion 
that the lethargic afternoon period does not obtain so markedly as in G. palpalis. 
Noteworthy in this connection is the case cited on page 201, when, on a moonlight 
night, while crossing a dried up swamp about 10 p.m., we were literally attacked 
by a swarm of quite 100 to 150, whereas, when we were crossing the same place 
in the afternoon at 5.30, not a single specimen was seen. 
Prey.—There can be little doubt that G. morsitans attacks man and animals 
with equal avidity, but the case mentioned on page 207 is worthy of consideration. 
On this occasion when riding round a sharp bend in the road I came suddenly 
upon a large troop of dog-faced baboons in an open clearing of considerable size ; 
these slowly scampered away, but left in their train an enormous number of 
G. morsitans, which had evidently followed them from the surrounding bush. 
They were, in some cases, over 400 yards from shade, and that at practically the 
hottest part of the day. Never have I seen as many G. palpalis so far away 
from shade ata similar hour. The predilection, if such it may be, of tsetse for 
monkeys has been noted by the Mandingoes, for they have named these insects 
“congo fin jolo” or “the biting fly of the monkey.” An examination of the 
blood of these baboons as a potential reservoir of trypanosomes might well repay 
the trouble. It is not at all evident why the rate of mortality amongst cattle is 
so high and still higher amongst horses in the Niumi Province. It is certainly not 
due to an overwhelming excess in the number of G. morsitans, but may in part be 
due to the fact that there is no region beyond the river area to which cattle can be 
withdrawn in the rainy season, and consequently they have to stand or fall under 
the full tsetse scourge during this period. The large amount of game confined 
in this smail area may, however, act as a reservoir, and as these form the food 
supply of the tsetse, the percentage of infective morsitans would be relatively 
high, which might account for the enormous mortality. The same may apply to 
G. palpalis and the large percentage of human trypanosomiasis infections in 
Essau, for example. At any rate an examination of the blood of such game 
might well reward the investigator. Another fruitful line of research may be 
indicated here, namely the part played by Stomoxys as a protozooal carrier, 
IX. Remepiat MEAsurRES AND RECOMMENDATIONS. 
Beyond pointing out that this town is by no means free from mosquitos, it is 
not my intention to suggest anything with regard to Bathurst, as this is the 
province of the Senior Sanitary Officer, and as remedial measures are being very 
