1. Fly rounds and reconnaissances about Sambala have indicated the following types of fly community: (a) Compact “female centres” characterised by frequent passage of game, and showing high apparent female percentage and often apparent concentration of fly; (b) “spread centres” over larger areas believed to be comparable in function to true, compact “female centres”; (c) “male areas” spread over large areas of Berlinia-Brachystegia and sometimes other kinds of wooding, where the apparent female percentage is low; (d) areas where fly is scarce.

2. Investigation of these phenomena by field experiments and other methods has led to the conclusion that the “female centres” and “spread centres” are most probably feeding-grounds of fly, and that the “male areas” are its home.

3. It is difficult to draw reliable conclusions from fly-rounds on the apparent variations of fly numbers in time, in relation either to season or to movements of game.