14 



to post-mortem changes), with a larger or smaller clove-brown blotch 

 (sometimes indistinct or almost wanting) near each basal angle of the 

 second segment, and the third to the sixth segments, inclusive, each 

 with a very conspicuous clove-brown transverse band, interrupted in 

 the median line, not reaching the lateral margins, and not extending 

 beyond the basal three-fourths of the segment, if so far ; legs buff, 

 last two joints of hind tarsi clove-brown or black, last two joints of 

 front tarsi and penultimate joint of middle tarsi conspicuously tipped 

 with clove-brown or dark brown, last joint of middle tarsi entirely 

 dark brown above in typical race, otherwise distal half or third of last 

 joint of middle tarsi alone dark brown or clove-brown, remainder of 

 joint merely brownish or even entirely pale." 



From the economic point of view Glossina morsitans is, after G. 

 palpalis, the most important of the Tsetse-flies, since not only is it 

 chiefly responsible for the dissemination of Nagana, or Tsetse-fly 

 disease of domestic animals, but, as has already been stated, 1 in 

 Nyasaland and Rhodesia it likewise transmits Trypanosoma rhodesiense, 

 the cause of sleeping sickness in those regions, where G. palpalis does 

 not occur. 



" Glossina morsitans, Westw., once regarded as an exclusively South 

 African species," writes Austen, " is unquestionably the most widely 

 distributed of existing Tsetse-flies, since its range extends from Sene- 

 gambia (about 16 N.) in the north-west, to southern Kordofan (about 

 12 N.) and southern Abyssinia in the north-east, and thence south- 

 wards to the Bechuanaland Protectorate (Lake Ngami district), the 

 north-eastern Transvaal and Zululand. Although present knowledge 

 is not sufficient to enable us to state whether G. morsitans exists in 

 every country and Protectorate within the limits indicated, the species 

 (besides occurring in the countries already mentioned) is certainly 

 found in : the Gambia, French Guinea, the Gold Coast (Northern 

 Territories), Togoland, Dahomey, Northern Nigeria, Belgian Congo 

 (Katanga District), 2 the Bahr-el-Ghazal Province of the Egyptian 

 Sudan, the Uganda Protectorate, 3 German East Africa [Tanganyika 

 Territory], the Nyasaland Protectorate, Rhodesia (N.-E., N.-W., and S.), 

 and Portuguese East Africa." According to H. Glaser, no species of 

 the Glossina morsitans Group exists in Cameroon. G. morsitans itself, 

 however, occurs in French Congo, though, according to Jamot (76), 

 there are but few places in the Ubangi-Shari district where the fly 

 is very numerous. 



Glossina morsitans shares with G. palpalis the distinction of being 

 the Glossina upon which most observations have been made during 

 recent years, and of which the largest number of specimens have been 

 collected. Moreover, although not the first member of its genus to 

 be discovered, " it was to G. morsitans that the name ' Tsetse ' was 

 originally, and indeed until a few years ago exclusively, applied" 

 (Austen), while it is the only species mentioned in the accounts of the 

 earlier African explorers of the nineteenth century, such as Livingstone 

 and others. 



1 P. 8, note !. 



2 In the Welle district of North-eastern Belgian Congo, where, according 

 to Rodhain (113), G. morsitans is also met with, it occurs only in the extreme 

 north-east, its area of distribution representing the south-western limit of the 

 Sudanese extension of the species. 



3 It is stated by Dr. S. A. Neave that Glossina morsitans, Westw., has not 

 yet been shown to occur in Kenya Colony ; in Uganda, it appears to be confined 

 to a little-visited zone, of comparatively limited extent. 



