BITING FLIES IN BRITISH EAST AFRICA 91 
that the females of all the species bite, and in the case of 
Glossina and Stomoxys the males also. The result of this is 
that they are frequently seeking the collector quite as much 
as he is seeking them ! 
The following hints may, however, prove useful. All flies of 
the family Tdbanidae, so far as is known, spend their larval 
state in water or at least damp mud or sand, so that there is 
always a greater probability of finding them near rivers, swamps, 
or such damp localities. The male Tabanidae are distinguished 
at a glance from the females by their huge eyes which occupy 
the entire head, there being no distinct division between the 
two eyes as there is in the female. Since they do not bite, 
special methods must be adopted for collecting the males, which 
are much less well known than the females and are compara- 
tively rare in collections. 
The genus Tabcmus, in British East Africa at least, seems 
to be much better represented on the low ground than on the 
higher plateaux. 
The females travel comparatively long distances from water, 
following cattle, &c., in search of food. Canvas, especially if 
damp, is curiously attractive to them, so that if at all numerous 
some are nearly certain to find their way into the traveller’s 
tent. Herds of cattle or other domestic animals in the 
neighbourhood are also well worth examining. These flies 
are usually to be obtained only during the heat of the day and 
seem to prefer bright sunshine. The beginning and again 
towards the end of the rains are usually the best times for this 
genus. The males should be sought for chiefly at the end of 
the dry season or during an early break in the rains. They will 
then be found drinking at damp sand or mud in stream beds. 
Much depends on locality, as a running stream affords a less 
chance of locating them than when there are only a few pools 
in the river bed. The males can also be sometimes obtained 
by careful search on the reeds at the water’s edge or occasionally 
sunning themselves on the boughs of trees overhanging the 
stream. I have never myself found the males any great distance 
from water. 
The genus Haematopota somewhat resembles Tabanus in its 
habits, but during the rains at least is almost universally 
