59 



A PRELIMINARY REPORT ON THE PROBLEM OF CONTROLLING 



GLOSSINA IN NYASALAND. 



By W. A. Lamborn, M.B., 

 Imperial Bureau of Entomology. 



On initiating this investigation my first aim was to discover a small isolated fly 

 area, such as those described as " primary fly centres " by Dr. Shircore (Bull. Ent. 

 Res., v., pt. 1, p. 87), with a view to carrying out experiments in the clearing of 

 bush and endeavouring to reduce the numbers of the fly by systematic capture 

 on a large scale. 



With these objects in view I decided that I could not do better than proceed to 

 the sleeping sickness area discussed in the paper referred to ; but owing to much 

 delay in the course of my voyage out, I did not arrive until almost the end of the 

 dry season, so that it was only possible for me to examine two of the " primary fly 

 centres " before the rains, though the remaining two were examined subsequently. 



On examination of the Nyansato district (see Dr. Shircore's map facing p. 90), in late 

 October and early November, before any rain had fallen at all, the fly was found over 

 a very large area, which commenced about 2 miles from Domira Bay and extended 

 nearly to Matumba's villages, a distance of about 8 miles in a direct line from east to 

 we»t. Detours were then made so as to enter the district directly both from the 

 south and from the north, the result being that in a direct line from south to north 

 the fly was found over an area of 10 miles, extending right up to the edge of the 

 clearing made round Mtalamanga's chain of villages. The observations made in 

 this locality were confirmed subsequently in the course of frequent visits for the 

 purpose of studying the fly. 



The Lingadzi district was then examined, also before the rains. The fly was found 

 sparingly a mile to the north of Mtalamanga's, at no great distance from the edge of 

 the clearing, and a little further to the north it was obtained in numbers over a 

 distance of approximately 10 miles in a direct line as far as the Chitua River, far 

 beyond the Lingadzi. From east to west fly extended in this region from a point 

 2 miles west of the dambo at Makko, along the course of the Lingadzi for 10 miles 

 in a westerly direction. 



The examination of the Kuti marsh district and of the Patsanjoka marsh district 

 was only completed after the onset of the rains. The fly distribution in these areas 

 was then found to be continuous, extending from east to west for 15 miles, and from 

 the Lintipi River in the south right up to Nyansato in the north, approximately 

 15 miles in a direct line. 



To summarise my observations : — No evidence of the natural splitting of the 

 northern portion of the fly area in the dry season into two small localised patches 

 was found, though two large areas do certainly exist as a result of the subdivision 

 of one larger one by native clearings ; and in the southern portion, examined after 

 a few scanty rains, the two so-called ** primary centres " were certainly continuous 

 with each other and with the northern portion of the area, the fly extending over 

 so large a region as to make one sceptical in regard to the possibility of their limitation 

 to within narrow patches so short a time before. 



