In the Sudan, as in other parts of Africa, where tsetse-flies (Glossina) are known to occur, the distribution of the species is always a matter of considerable interest, owing to the fact that some are known to be disseminators of disease and others are suspected as being possible carriers. Of the twenty species so far recorded from the continent of Africa, nine have been experimentally proved to be capable of transmitting trypanosomes pathenogenic to man or his domestic animals. As yet only five species have been found in the Sudan, namely, G. palpalis fuscipes, G. morsitans, G. longipennis, G. fusca and G. fuscipleuris, and of these the first four are known to be carriers of trypanosomiasis.