152 JAS. J. SIMPSON— ENTOMOLOGICAL 



and so come in contact with those already interested in such work, or, by explain- 

 ing the aims and methods of the Entomological Research Committee, to secure 

 the co-operation of those who might be persuaded to aid in the scheme. 

 Consequently, it was impossible for the writer to do any actual experimental 

 work or devote any time to the study of life-histories or such-like investigations 

 in any special locality. The report must, therefore, be considered as a general 

 geographical survey, and taken with other notes and papers published .... 

 forms a resume of recent work. Further it is hoped that it may serve to show 

 not how much, but how little, is known of this aspect of the subject. , ' 



The Colony and Protectorate of Sierra Leone was traversed by the writer 

 from March to NoA^ember 1912, and the report, therefore, deals mainly with 

 observations made during that time, but incorporated with these are the results 

 obtained by other officers, chiefly medical, stationed in the Colony, to whom the 

 thanks of the Committee are due. 



The table of contents shows the general arrangement adopted, but a few words 

 are necessary in explanation of this. I have laid great emphasis in previous 

 reports on the factors which influence the distribution of the vaiious blood- 

 sucking insects, and have shown how geographical situation, various topograph- 

 ical features, climate, rainfall and humidity, the length and duration of the wet 

 and dry seasons, and the various types of vegetation all have a bearing on such 

 distribution. In this report I have also added two short chapters dealing with 

 these aspects in Sierra Leone. 



The arrangement of the material in the narrative always presents difficulties. 

 It is obviously out of the question to discuss the various political divisions, as 

 these are purely arbitrary and in no way connected with this subject. In the case 

 of Sierra Leone the various routes adopted were chosen so as to follow as far as 

 possible the different river systems, and consequently the narrative follows more 

 or less closely the order in which the different regions were visited. With the 

 aid of the appended map, any one desirous of doing so may easily collate all tiie 

 information available for any particular district. 



A list of all the blood-sucking insects and other arthropods so far known 

 from Sierra Leone has been drawn up for reference, but it must be noted that 

 several new species await description, and doubtless further research will 

 add more. 



A ma]) has been added showing the distribution of the various species of 

 Glossina, and the route followed by the author has been indicated so that it will 

 be easy to locate any place mentioned in the text. It might be noted that a 

 large number of villages not shown on the origiual map (Gr.S., G.S., no. 2082) 

 have been added in red. 



Sufficient has been said to indicate the lines along which this report was 

 possible and on which it has been framed, and it is to be hoped that this resume 

 of work done may help to stimulate others to an elucidation of the important 

 bearing of insects in relation to disease, to indicate lines along which such work 

 may be most profitably accomplished, and to point out the means by which these 

 pests may be diminished in number, and, if possible, eventually abolished. 



