Seeing that Glossina morsitans, the typical “tsetse” fly of writers on South Africa, has been well known for perhaps a longer period than any other member of the genus, it is a matter for great surprise that much of its life history is yet entirely unknown. A large mass of literature, dealing with its general habits, is extant, but the breeding habits and the larva have not been described. It is noteworthy that only last year a single specimen of the puparium was discovered for the first time, and when the wide distribution, the great plentitude, and the economic importance of the fly are considered, this becomes all the more remarkable.