The history of tsetse-fly in Southern Rhodesia up to the present year (1918) continues on the whole to be one of expansion, although on the other hand one small, but important, belt appears to have become extinct. In addition, a fly area in the Moçambique Company's territory has extended up to our eastern border, with the result that serious losses of cattle from trypanosomiasis have occurred on the farms in that region. Detailed reports on the advance or retrogression of Glossina morsitans in other parts of Africa appear to be lacking, and it is felt that in view of the position of this territory in relation to tsetse-fly a review of the situation to the present day may not be without general interest.