The following report is the fourth of a series dealing with the blood-sucking insects which are or may be implicated in the transmission of disease in man and other animals. The previous reports have appeared in different issues of this Bulletin* and should be consulted in conjunction with this, as many aspects of a general character, which are equally applicable to all West African Colonies, have been discussed there and need not therefore be reiterated here.

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.

For the past two years the writer has studied the Oriental CULICIDAB at intervals, with a view to preparing a tabular synopsis of the species. During this time it has become evident that a large number of names will have to be rejected or changed in some way, and it seems desirable to call attention at once to some of these proposed changes, as it will inevitably be a considerable time before the thorough revision of the Oriental mosquitos which the writer has in view can be published. The present paper is intended merely to deal with nomenclatorial questions, points of systematic interest being introduced only in so far as they are necessary to explain or justify the writer's conclusions. The classification here indicated may be taken as approximately final, but the limits of certain genera and their arrangement may ultimately require modification, while their number may not improbably have to be reduced. Over 80 specific names are here for the first time definitely sunk, while the probable synonymy of 8 or 10 others is suggested. On the other hand two new names are proposed owing to the preoccupation of the original designation of the species.

The subject which I propose to introduce is one which is of such very great importance in agricultural practice in different parts of the world that I trust it may not be out of place to give a brief account of the experiments in connexion with it, which we have been conducting in Egypt and which, although still incomplete, indicate very favourable results.

Uganda is a particularly favourable country for the development of insect life, as vegetation grows very luxuriantly and there is no great variation of temperature for any length of time, and insect growth and1 multiplication are therefore continuous throughout the year. This is especially true with regard to the COCCIDAE.