In 1913 Major Austen asked me whether it would not be possible to reproduce artificially the conditions which tempt the female Glossina palpalis to deposit its larvae (Report of Departmental Committee of Colonial Office on Sleeping Sickness, June 1914. Questions 1420, 1421) I replied that I thought it would, and early in 1914, on my return to Uganda, commenced a preliminary experiment to test the possibility of reducing the numbers of palpalis by providing highly attractive artificial shelters under which larvae would be deposited in numbers, and where the pupae could be collected easily and regularly destroyed. These preliminary investigations were described in my Fifth Report on the bionomics of palpalis published in the Reports of the Royal Society's Sleeping Sickness Commission (No. xvii), and it was claimed that these results were sufficiently promising to make the method worth attention and further experimental trial. Before I went on long leave in 1919 I had arranged for such a trial to be carried out in my absence, but the experiment came to an end from causes beyond my control before a satisfactory result could be obtained either confirming or contradicting the claims made for the method.