GLOSSIXA AXD STOMOXYS. 



5 



the true house-fly (for which both are no doubt often mistaken), 

 while the former is only about half its size.* 



Apart from the prominent proboscis and the mode of carrying 

 the wings when at rest, there is nothing in any way remarkable 

 or striking about the appearance of a Tsetse, and the descrip- 

 tions of most travellers emphasise this fact. As already 

 mentioned, species of Stomoxys and Hsematapota are most likely 

 to be mistaken for G/ossina, and apart from these confusion 

 can hardly take place. The females of both genera are greedy 

 blood-suckers, and often torment domestic animals very greatly. 

 Of Stomoxys, which, as is shown in Chapter III., is a 

 near ally of Glossina, several species (all closely resembling, 

 though apparently distinct from, the European Stomoxi/s cal- 

 cifrans, Linn.) are found in Africa, and in the abdomens of 

 specimens of one of them in the British 

 East Africa Protectorate, the late 

 Captain A. J. Haslam found the 

 Tri/panosoma of Nagana, or Tsetse-fly 

 disease. Although Stomoxys also has 

 a prominent proboscis, it is not en- 

 sheathed in the palpi, and is conse- 

 quently much more slender than the 

 proboscis of Glossina. The species of 

 the former genus are little greyish flies 

 with black markings ; they are much 

 smaller than Tsetse-flies, and since 

 their wings when in the resting posi- 

 tion, instead of closing one over the 

 other, diverge at an angle (see Fig. 3), 

 like those of Musca domestka, it is easy 

 to distinguish them. Heematopola, on the other hand, which is 

 a genus of small horse-flies (Family Tabanidfe) often known as 



* The average Musca doinestica in Europe measures about 3 lines (6 to 

 7 millimetres, or slightly more than a quarter of an inch) in length, aiid 

 has a wing-expanse of between 7 and 8 lines (from 15 to 16 millimetres) ; 

 therefore it is in reality decidedly smaller even than a small specimen 

 of Gl. morsitans. In the Tropius and hot countries generally Miisca 

 domestica is usually somewhat smaller than in Europe. The common 

 house-fly justifies its name, for its distribution is now practically vi'orld- 

 wide, as it has been carried by ships to all quarters of the globe. As 

 regards South Africa, swarms of house-flies are mentioned by Lichtenstein 

 ^Hinrich Lichtenstein: "Roisenim siidlichen Africa in den Jahren 1803, 

 1804, 1805, and 1806" (C. Salfeld : Berlin, 1811), pp. 192-193) as infesting 

 houses near the Karroo, in Cape Colony, in the early years of the 19th 

 century ; while Musca domestica was at certain seasons one of the pests 

 of our troops in standing camps during the late campaign. 



Fig. 3. 



Stomoxyx sp., from Natal, in resting 



uttitucle, shovving the position 



of the wings, (x 4.) 



