The presence of trypanosomiasis in cattle in the Province of Mozambique has made the question of tsetse-flies one of considerable interest and importance. During the past two-and-a-half years the writer has lost no opportunity of gathering information as to the whereabouts of tsetse-belts. It has been very difficult, because of the inaccessibility of most parts of the Province. The northern districts of Nyasa and Mozambique, for example, are practically impenetrable except for a few miles along the coast; no roads exist, and the natives, while not actively hostile, do not favour the intrusion of the white man. The northern part of the Zambesia district and the Tete district are likewise seldom visited by white men. It was not possible to organise a system of collecting reports of fly-belts from officials because of the small number of officials in these out-of-the-way regions. The writer has, however, been enabled to visit practically all accessible parts of the Province, and by questioning officials and natives and those who have been through the more inaccessible regions, has gathered considerable data. Specimens of fly have been secured from many of the places recorded. Although the few notes given are by no means complete, it seems best, however, to place them on record now.