172 DR. SCHWETZ. 



With regard to G. palpalis, although it occurs almost throughout Lukuga, I saw 

 but one specimen, and that in the railway carriage, in my double journey (going and 

 returning). 



In brief, I would say that from the Niemba to Tanganyika almost all along the 

 railroad three species of Glossina exist : palpalis, morsitans and brevipalpis. All 

 three species are so rare close to the railway itself that they need scarcely be reckoned 

 with as regards passengers, either human or animal. It is quite different for those, 

 either Europeans or natives, who have to live close to the railway and to the river 

 and who are constantly moving about in the vicinity. 



First Section. 



There is no need to be a specialist, or particularly observant to find tsetse between 

 Kabalo and Luizi. Some kilometres before Kabalo these flies begin to come into the 

 compartment when the windows are open. When closed, the flies can be seen trying 

 to enter, stuck, as it were, to the windows. Coming in the train from the opposite 

 side, from Tanganyika, it is at some kilometres distance after passing the Luizi that 

 the same phenomena are observed. Not only are the flies constantly seen, but they 

 are also felt. I do not think that there are many passengers who have travelled over 

 this region without being bitten by a tsetse. It is common knowledge here that this 

 fly is G. morsitans. But it is not common knowledge that, besides G. morsitans, two 

 other species exist here, namely pallidipes and brevipalpis. G. pallidipes is common 

 enough here and exists in this section all along the railway, although in much smaller 

 numbers than G. morsitans. I have seen pallidipes at km. 25 and 16 (where I stopped) 

 and particularly between km. 25 and Kabalo, during a ride in lorries. G. brevipalpis 

 on the other hand is very rare here. I have seen only a very few specimens in the 

 vicinity of km. 15. This is the more surprising as at the same latitude, west of the 

 Lualaba, brevipalpis is very common. 



Second Section. 



The study of the Glossina of the second section is as complicated and difficult as 

 that of the first section is simple and easy. Practically speaking, from the point of 

 view of passengers, there are not any tsetse in this section. 



In coming from Lualaba, there may be one or two morsitans still in the train after 

 the Luizi, just as in coming from Tanganyika, or from the Lukuga, there may still be 

 in the train a morsitans or a palpalis long after the Niemba is passed ; but these are 

 imported flies, at any rate so far as morsitans is concerned, for this species does not 

 occur along the second section of railroad, or exists in such small numbers that I have 

 not found it. And yet, if the second section is much poorer in Glossina in general, 

 as regards quantities, than the other sections, it is richer than the other sections in 

 the number of species. 



While the first and third sections possess a vegetation more or less uniform, and 

 the Glossina found there are more or less regularly distributed, it is different in the 

 second section, where the vegetation is polymorphous and transitory, and where the 

 Glossina are consequently localised. (I cannot of course repeat in each of my papers 

 the relations between the vegetation and the different species of Glossina: These 

 relations have been explained in several articles that I have published in various 



