The account of the entomological work carried out by the writer in Southern Nigeria falls naturally into three sections, October-December 1911, January-June 1912, and June-October 1912. During the first period, work, principally on cotton pests, was carried on at the Agricultural Headquarters, Ibadan, particular attention being devoted to the Red Cotton Stainer Bug. The second period was given to travel (fig. 1), when the entomological problems of the different districts were studied on the spot, and lectures were given en route to meetings of native chiefs, native agricultural societies, schools and school teachers. The third period was spent in dealing with the insects of nursery cocoa, cotton, maize and yam. Lectures and demonstrations were given to agricultural pupils. A small amount of work with insecticides was attempted. In conjunction with the Mycologist, rules were formulated for conducting the three first Fumigatoria of the Colony.