306 MR. S. A. NEAVE — REPORT ON A JOURNEY 



season, it is difficult to see where suitable breeding grounds could occur. I 

 cannot agree with Dr. Leach's suggestion that the fly might migrate in the 

 wet season to the smaller streams in search of suitable breeding grounds ; 

 for the banks of such streams at this time are liable to even more sudden 

 and violent inundations than those of the larger rivers. 



It must be remembered that practically the whole of the low ground in 

 the Luang wa Valley is covered with deep alluvial soil, generally of a sandy 

 nature, in which the rivers at time of flood cut deep and frequently shifting- 

 channels. 



Glossina morsitans calls for comparatively little comment. It is practi- 

 cally ubiquitous on both sides of the valley, southward from a point approxi- 

 mately level with the junction of the Luwumbu River. A phenomenon 

 observed by the author on the south-west shore of Lake Nyasa was also 

 noticeable here — namely, that the fly rather avoids, than otherwise, the 

 immediate vicinity of the river or lake, though generally abundant enough 

 half a mile or less inland. The insect of course frequently follows man or 

 animals to the bank, but is, I think, seldom resident there. 



There can be no doubt whatever that G. morsitans has spread enormously 

 within the last five years in the Luangwa Valley. The author visited one or 

 two localities in the Petauko district where this species is now swarming, 

 but where it was certainly not present when he was there in 1904 and 

 1905 *. There appears to be, however, a general consensus of opinion among 

 the older natives that in these cases it is not realh^ invading new areas, but 

 is recovering the ground lost at the time of the rinderpest, some fourteen 

 years ago. 



Glossina fiisca. — The history of the few specimens of this species dis- 

 covered to date appears to be as follows : — 



In December 1904, or January 1905, the writer obtained a single specimen 

 close to Hargreaves. This specimen is now in the Hope Department, Oxford 

 University Museum. 



On arriving at this locality on the present trip, in the month of September, 

 the writer was informed by Mr. C. R. Rennie, the Acting Assistant Magis- 

 trate at Petauke, that he had obtained through natives a few specimens in 

 two other localities in the same district : — 



(1) On the Chirimanyama stream at the point where the main road crosses 

 it, and about eight miles west by south of Hargreaves. This stream is 

 running all the year at this point. 



* [Mr. E. E. Austen has in his possession a letter written by Mr. Chesnaye in December 

 1903, and another written by Mr. H. Thornicroft (Native Commissioner, Petauke) in 

 May 1904, in both of which reference is made to the occurrence at that time of G. morsitans 

 at Molilo's village and between Petauke and the Nyimba River. The late Mr. Codrington 

 also sent to the British Museum several specimens of this species which were captured in 

 these localities in June 1904. — Ed.1 



