XV] TSETSE-FLIES 243 



. /Arista feathered only on dorsal surface . . . . . . . . =5 



\ Arista feathered on both dorsal and ventral surface . . . . =6 



Proboscis long and tapering ; fourth longitudinal vein gently curved 

 distally so as to leave the first posterior cell wide open ; third longi- 

 tudinal vein without bristles . . . . . . =Lyperosia. 



Proboscis short and stumpy ; first posterior cell narrowly open ; third 



I longitudinal vein with some bristles proximally =Stygeromvia. 



("Fourth longitudinal vein strongly curved distally, so as to leave first 



posterior cell narrowly open. Third longitudinal vein without 



bristles . . . . . . . . . . . . =Hcsmatobosca. 



I Fourth longitudinal vein slightly curved distally. so as to leave first 

 t posterior cell widely open . . . . . . . . . . = 7 



/Third longitudinal vein with some bristles proximally =HcBmatobia. 



\ Third longitudinal vein without bristles .. .. =Bdellolarynx. 



CHAPTER XVI 



THE TSETSE-FLIES — GENUS GLOSS/NA, WIED., 183O 



Diagnosis. The genus Glossina is sharply distinguished from 

 all other members of the Muscidae by its viviparous mode of 

 reproduction, which resembles that of the Pupipara, and also 

 by certain peculiarities in the structure of the antennae and in 

 the wing venation. Austen gives the following diagnosis of 

 the genus : 



" Narrow-bodied, elongate, dark brown, blackish, yellowish-brown, or 

 yellowish flies belonging to the Family Muscidae, ranging in size from about 

 6 or 8 mm. in the case of Glossina tachinoides , Westv/., to as much as 13 or 

 I3"5 mm. in that of a large female of G. brevipalpis, Newst., or longipennis, 

 Corti ; recognisable when alive and at rest by the wings being closed fiat one 

 over the other above the abdomen (beyond which thej' project considerably), 

 instead of divaricate (as in the case of Stomoxys) or tectiform (as in HcBmato- 

 pota), and by the proboscis {i.e. proboscis ensheathed in the palpi), projecting 

 horizontally in front of the head ; palpi, as seen in the natural position, extend- 

 ing slightly beyond the proboscis, their inner sides grooved so as to form a 

 sheath for the latter, to which in life they are applied so closely as entirely 

 to conceal it ; base of proboscis suddenly expanded beneath into a large onion- 

 shaped bulb." 



General description. In addition to the above-mentioned 

 characters, there are certain others which aid in the differentia- 

 tion of the genus. The antenna, in both sexes, contains in the 



16 — 2 



