RESEARCH IN BRITISH WEST AFRICA. 303 



it does not iu any way aim at being exhaustive, but by showing how scanty our 

 knowledge of this subject is, it may stimulate others to collect and make 

 observations on the various species of insects which are harmful or beneficial to 

 man and animals. 



For a proper understanding of the distribution of not only tsetse but also other 

 insects, several general considerations have to be taken into account ; for example, 

 the geographical position of the Protectorate, the general topography, the river 

 systems, the nature and extent of the various types of vegetation, the climate 

 and the rainfall. Each of these has been discussed in a very general way, only 

 in so far as they are likely to influence the problems with which we are here 

 more intimately concerned. 



A short section has also been added on the chief tribes inhabiting the 

 Protectorate, as, to a great extent, their distribution and mode of life have often 

 a direct bearing upon the dissemination of disease. 



Several photographs (PI. viii.-xv.) and two sketch maps (PI. vii. and xvi.) 

 have also been included to illustrate some of the points emphasised in the report. 

 The former serve to show the various types of country either associated with 

 or free from certain species of Glossina. The first sketch map illustrates the 

 general contour lines and river systems, while the second has been added as the 

 region it depicts is uncharted on the larger map. 



The most recent map (scale 1*014 inches = 32 miles) of the Protectorate has 

 been reproduced to show the distribution of the various species of Glossina which 

 occur there, and in it have been inserted all available authentic records, including 

 those in the National Collection in the Natural Plistory Museum. In another 

 paper in this Bulletin,* I have discussed the question of the graphic representa- 

 tion of the distribution of insects and disease on maps, and have suggested a 

 scheme which has been adopted in the compilation of the present map, and which 

 will be used in all maps published in colour in this Bulletin, and also in that of 

 the Sleeping Sickness Bureau. 



The various sections in the Narrative do not follow the order in which the 

 different parts were traversed by the author, but are arranged so as to form a 

 more or less complete unit, and the whole route is shown on the accompanying 

 map. 



A list of the blood-sucking insects and ticks hitherto recorded fi-om Northern 

 Nigeria has been drawn up as a guide to those interested in this work, and notwith- 

 standing the fact that the number of species is already large, there is little doubt 

 that many new species will be found to occur, chiefly in the northern part of the 

 Protectorate. 



I. Geography of the Protectorate. 



(a.) Position and Extent. 



The Protectorate of Northern Nigeria, the largest and most recently acquired 

 of the British West African Possessions, is roughly rectangular in shape, and 



* Bull. Ent. Res. II, pt. 4, pp. 297-299. 



