This short paper summarises and discusses the entomological results obtained from marking experiments done with Glossina morsitans at Kakoma, Tabora, Tanganyika Territory, from July 1938 to May 1940. The first eighteen months' data and results have been given in full elsewhere (Jackson, 1941) and the mathematical treatment explained. The marking experiments occupied three days weekly, and covered an area of 16 square miles of annually fired woodland and seasonal swamp; a similar area was observed in the same way for a year in country protected against fire, and in addition a number of special experiments to check results were carried out. The climate and situation of Kakoma have already been described (Jackson, 1937) for the year 1935; from that year until April 1938, smaller scale routine marking experiments were carried on with few interruptions, so that there is available a fairly complete body of data collected over nearly five and a half years.