The larvae burrows itself head first into the soil. The buried larvae is shown in a time-lapse sequence pupating into a black puparium. An x-ray of it shows the two moults that take place in the pupae; the first producing the pupa, the second the imago. A man in woodland collects tsetse flies for laboratory work. We are shown in close-up how the imago breaks the anterior end of the puparium and struggles out underground, then crawls to the surface. A further time-lapse sequence shows the imago at rest while its wing veins fill with fluid, then dry out. The fly searches for a new host and the life cycle is complete.