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NOTES ON GLOSSINA MOESITANS, WESTW., IN THE 

 LUANGWA VALLEY, NOETHEEN EHODESIA. 



By Ll. Lloyd. 



Entomologist to the Luangwa Sleeping Sickness Commission. 



These notes are intended as a summary of the early investigations into the 

 habits of Glossina morsitans carried out in connection with the Luangwa Sleeping 

 Sickness Commission. The part of the valley that has been examined is that 

 lying between 12° S. and 13° 50' S., but it has been practicable to make only one 

 journey to the eastern side of the river. This journey was undertaken in 

 September and consisted of an examination of the Eukususi and Eukusi Eivers 

 from the Luangwa almost to the Nyasaland boundaries. Hence these remarks 

 apply mainly to the district immediately surrounding Nawalia, the headquarters 

 of the Commission. The observations have been made during the period from 

 August 1911 to the beginning of March 1912. 



Physical features and climate. 



These have been dealt with on several occasions,* but a few remarks here are 

 necessary. The Luangwa is a broad sluggish stream running through an alluvial 

 plain, at this point about thirty-five miles in breadth. In the dry season there 

 are extensive sand-banks in its bed. On the western side low hills arise at the 

 edge of the plain and the range is continued to the precipitous Mchingas. The 

 laboratory is situated on the first of these hills, at an altitude of 2,000 feet, while 

 the Luangwa is about 100 feet lower. The hills are interspersed by shallow 

 hollows filled with alluvial soil, through which the streams cut deep channels. 

 Apart from the Nyamadzi and the Mpamadzi, which are perpetual streams, these 

 channels contain no water, except for a few hours after rain, when they assume 

 the proportions of torrents. On the eastern side there is no running water during 

 the dry season, the beds of the streams becoming filled with a dense growth of 

 spear-grass. The whole valley from June to December is very dry. A few hot 

 salt-springs in the neighbourhood of Nawalia form permanent swamps of small 

 proportions and near the Luangwa a few pools persisted until the rains began. 

 The ground is baked so hard that it becomes difficult to penetrate it, and in the 

 plains broad and extensive fissures form which extend deeply into the earth. In 

 the rainy season the plains become very swampy, swamps being common on 

 sloping ground in the hills where the short tufty grass retains the water for days 

 after rain has fallen. 



The vegetation for the most part is not dense. The mopani forest, which 

 extends over most of the plains, is of an open nature with little or no under- 

 growth. It consists almost entirely of one kind of tree, the mopani ( Copaifera 



* Neave, Bull. Ent. Res. I, p. 303. 



