This article investigates the anti-tsetse fly work of colonial entomologist K. R. S. Morris in the Northern Territories of the Gold Coast between 1928 and 1951. Morris's main programme was directed at the Lawra District of the north-west, where he claimed to have eliminated the tsetse population and trypanosomiasis by the end of his tenure. This achievement allowed farmers to move into the formerly infested land and reclaim the area for agricultural development. As an added benefit, Morris also claimed, eliminating tsetse flies in the Lawra District reduced the incidence of sleeping sickness in the main market towns of north-west Ashanti. The article charts Morris's work, which is historically significant for a number of reasons. First, it reveals much about the connection between anti-tsetse work and colonial development doctrine in northern Ghana. Second, it highlights the importance of studying colonial practices. Morris's clearing programme appears to have worked, but it was almost certainly based on faulty theories of tsetse ecology. In this sense, the story of anti-tsetse work in the Northern Territories shows that we might learn as much from colonial practices as from colonial ideologies.