170 DR. SCHWETZ. 



From the point of view of the landscape in general, and vegetation in particular, this 

 distance is divisible into three sections : — (1) from Lualaba to the Luizi River, 63 

 kilometres ; (2) from the Luizi Kiver to the Niemba River, 174 km. ; (3) from the 

 Niemba River to the Lake or Valley of Lukaga, 273 km. 



First Section. 



The route of this section forms almost a straight line, and the ground is flat or 

 slightly undulating. There is no stream in the neighbourhood of the railway. As to 

 the vegetation, the country is wooded a few kilometres from Lualaba, but becomes 

 gradually transformed into open, slightly wooded, meadow land a little before the 

 Luizi. A great thinning of the trees is noticeable between kilometres 25 and 28 and 

 again at kilometres 31 and 37. In certain places alongside the railway the trees are 

 less abundant ; probably this is an artificial clearing, the wood having been cut for 

 fuel for the locomotives, steamers from Lualaba, etc. This clearing, which is 

 frequently noticeable along the route, and which will doubtless become more 

 accentuated, ought certainly to have a great influence on the distribution of Glossina. 



The river Luizi flowing from Lukuga is nearly 40 metres wide where the river crosses 

 it. There are no f ordable places at the end of the dry season. The river flows through 

 a wide grassy valley, which is completely inundated in the rainy season. The banks 

 of the Luizi are entirely grass-covered, close beside the bridge as well as for a certain 

 distance up and down the river, but trees are visible at about one kilometre down the 

 river. 



Second Section. 



While the first section is uniform and easily described in a few words, so far as 

 vegetation is concerned, the second section presents different aspects in various 

 parts. 



Beyond the grassy valley and low-lying marshes of the Luizi the ground rises, and 

 after one or two kilometres of wooded plain again becomes park-like. But at km. 93, 

 that is after 30 km. of park, comes a low-lying plain about 5 km. long and relatively 

 little wooded, but with many borassus palms. At the beginning of this plain, at 

 km. 93, the Luambashi stream, flowing from the Loyeye, is crossed, the banks being 

 covered with climbing, bushy vegetation, and apart from some small pools of stagnant 

 water, I found it dry (October). After the plain, the vegetation becomes patchy and 

 alternates between park and forest. Sometimes there is, after several kilometres of 

 park, a stretch of forest, and sometimes small patches of forest are interspersed with 

 patches of park. Sometimes the vegetation is undefinable, being less thick than forest 

 and thicker than typical park land. Apart from numerous stretches of one or two 

 km. of true forest, the road traverses a stretch of tropical forest about 7 km. in extent, 

 notably between km. 131 and 138. Referring to the map, it is evident that from just 

 beyond the Luizi until just before the Niemba, and especially up to km. 166, the 

 railway follows closely the river Loyeye (a tributary of the Luizi). Thus the river is. 

 a considerable distance from the railway (never less than 4 or 5 km.), flowing in a 

 wide valley, while the railway follows a ridge bordering this valley. Little streams 

 flow down from this ridge, others follow at the base for a certain distance, and nearly 

 all these streams and their sources are surrounded by forest. It is evident, then, 

 that when the railwav follows beside a stream or its source it crosses or follows a band 



