90 BITING FLIES IN BRITISH EAST AFRICA 
least of which projects horizontally from the head. It is 
important to remember the combination of these two characters 
as there are harmless non-biting flies which carry their wings 
in the same way as the Tsetse. 
Being very local in their distribution in British East 
Africa these flies are unknown to many tribes of natives, but 
at Kibwezi, where there are three species, the Wakamba call 
them ‘ Chitangua.’ 
There are at least four species of Tsetse in the Protectorate. 
Two large species G. brevipalpis, Newstead (formerly known 
in East Africa as G.fusca), and G. longipennis. G. brevipalpis 
is one of the largest species and of a dark brown colour ; it is 
only on the wing in the morning and late evening and is seldom 
seen during the heat of the day except in dull weather. It 
frequents the banks of rivers, especially where there is a certain 
amount of cover. 
G. longipennis is another large insect, only a little smaller 
than brevi'pal'pis, but is much paler. It bites freely during the 
heat of the day and seems to be entirely independent of water, 
chiefly frequenting barren desert localities. Neither of the 
above species is definitely known to carry disease to man or 
animals in nature. 
G. pallidipes is a markedly smaller, brownish fly, also fre- 
quenting river valleys, though it is probably less dependent on 
water than brevipalpis. It bites at all hours of the day and is 
believed to carry disease to domestic animals. 
G. palpalis is the smallest of all the above described species 
and is very much blacker. It only occurs in British East 
Africa, so far as is known, in the Nyanza Province, and is 
confined to the belts of timber on lake shores and river banks. 
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As is well known to all, it carries sleeping sickness to man. 
The flies of the genus Stomoxys are small, blackish flies, 
very much like house-flies in appearance, indeed are frequently 
mistaken for them. A close examination will, however, reveal 
a rather long, stiff, somewhat curved biting proboscis quite 
different from the short soft mouth parts of the common house- 
fly and its allies. 
With regard to collecting the above described flies it is 
difficult to lay down any definite rules. It must be remembered 
