These studies were made in Uganda on the islands and shores of Victoria Nyanza, in territory which had been depopulated some years before on account of tsetse-fly and sleeping sickness. They were begun in October 1913, and extended over two full years, of which eighteen months were spent in the fly belt on Victoria Nyanza, and three months on a tour into Bunyoro, where for the time being (the spring of 1914) Glossina morsitans was the centre of greater attraction as a possible vector of human trypanosomiasis. Seven tours were made from headquarters at Entebbe—the shortest, of three days only, being interrupted by the War, and the longest, of eight full months, being much prolonged by the War.