62 



We are somewhat better informed as regards the western limit of 

 G. morsitans, which between the sixth and eighth parallels, in Dr. 

 Bequaert's opinion, is represented approximately by the course of the 

 Lualaba, on the left bank of which the fly would appear to exist only in 

 sporadic colonies. Further south conditions are different, and beyond the 

 eighth parallel G. morsitans has invaded the left bank of the river for 

 fairly long distances ; it occurs in abundance at Kikondja (between Lake 

 Kisale and the Lovoi River), and throughout the region comprised 

 between the Hakansson Mountains and the Lualaba. Below the ninth 

 parallel this Tsetse even extends slightly beyond the Lubudi ; its 

 western limit in this region seems to lie somewhere about Long. 25 E. 



Information is lacking as regards the most southerly part of Katanga, 

 between the Lualaba and Dilolo ; all that is known is that G. morsitans 

 does not exist at Kayoyo, or in the intervening district between this 

 post and Kinda post (Dr. Rodhain). 



Dr. Bequaert adds that it is a very remarkable fact that, while 

 G. morsitans is generally absent from the wide tracts of country lying 

 between the Lubudi and the Lubilash (Sankuru), Dr. Rodhain found 

 an isolated colony of this species near the Nzie (a small affluent of the 

 Lubilash, about Lat. 9 S. and Long. 24 E.), covering a space of 30 

 kilometres (18| miles). The Nzie colony represents the most westerly 

 point at which G. morsitans has been met with in Katanga. It is 

 probable that, beyond the regular area of distribution of the species, 

 there are other analogous spots at which the fly makes a sporadic 

 appearance, and it is eminently desirable that the entire south-western 

 region of Katanga should be explored in this connection by a pro- 

 fessional entomologist, capable of recognising the biological conditions 

 suited to G. morsitans in this country. 



In Katanga, G. morsitans frequents by preference the savannah 

 forest, where it is found even in the driest places and far from water, 

 although it is also actually met with on the rivers. 



It may be added that, as a general rule, Dr. Bequaert finds the habits 

 of Tsetse-flies much more elastic than they are represented to be by 

 the majority of authors. In Katanga G. morsitans may be said to be 

 fairly uniformly distributed everywhere, while in a given place the 

 insect may vary in numbers from one season to another, and even 

 doubtless from one year to another. It would be difficult to formulate 

 a rule on the subject, or to delimit fly-belts properly so-called. 



On the other hand it may be asserted and the fact is of considerable 

 practical importance that the highest parts of the tablelands of 

 Katanga are entirely free from G. morsitans. The fly is not met with 

 above 5,250 ft. in Manika (Biano), Kundelungu and Marungu ; in 

 Biano, to be precise, Dr. Pons found the last G. morsitans at an altitude 

 of 5,216 ft. 



According to statements published a few years ago by M. Bovone, 1 

 a veterinary officer, if G. morsitans does not exist in Marungu, a region 

 of lofty, dry and denuded plateaus, unsuitable for Tsetse-flies, it 

 nevertheless occurs in the regions adjoining this massif, especially to 

 the north, at Mulonde, along the Baudoinville road, and to the south- 

 west, where it has been encountered on the margins of the Lukifva, 

 seven and a half miles from the Marungu boundary. Lastly, it has also 

 been observed to the west of Lusaka village and along the Lufuko, while 

 M. Bovone has even met with it on two occasions at Mutambala's 



1 Bovone, " L' Agriculture et Felevage au Marungu " : Bull, agric. du Congo 

 beige, Vol. v., no. 3, p. 457 (Sept., 1914). 



