During the latter half of the year 1926, the writer collected parasites from rodents and insectivores in Nigeria. From 1st August to 20th October collections were made in the wet forest near Lagos; 26th October to 2nd November and 10th to 20th November in the guinea grass savannah near Ibadan and Oyo; 3rd to 7th November in the heavy rain forest at Ife; and 28th November to 11th December about Kano on the border of the desert. The animals were usually captured in traps, but a few were shot. They were always placed at once in tight cloth bags or wire cages in order that their ectoparasites might not escape. A general account of the character of the country where collections were made has been given elsewhere (Pearse, Science Monthly, xxv, 1927, pp. 228–239). My thanks are due to the late Major Ingoldby, of the British Museum, and Dr. Karl Jordan, of the Tring Museum. The former identified all the mammals and the latter helped with the identification of several of the fleas.