The Seasonal Abundance of Blood-Sucking Flies in a Grassed Woodland Area in Central Tanganyika

Abstract

Mpwapwa, lat. 6? S., long. 370 E., altitude 3350 ft., has an average annual rainfall of 26 in., all of which falls between December and April. The observations considered in this paper were made in the Kikombo valley, which is enclosed by steep hills rising to 6000 ft. above sea-level. A number of permanent stream* descend from these high hills, but in the dry season all disappear soon after reaching the flats. The Veterinary Department has a farm in the valley. In an attempt to discover in which parts of the bush surrounding the farm the tsetse fly Glossina pallidipes Austen was lurking, a number of 'flyrounds' were laid out. A 'fly-round' is a path passing through the terrain under investigation, along which at regular intervals, usually once a week, a party of three trained Africans (equipped in this case with a bait ox) proceeds, catching such flies as appear to them. These Kikombo fly-rounds were for the purpose of investigating G. pallidipes and the observations on other flies, recorded in this paper, were made only incidentally. Had the investigation of Tabanidae, etc., been a primary objective the flyrounds would have been sited differently-in particular a high-altitude round would have been included.