304 



Hominoxious Arthropods 



ff. Tarsi of the first and second pairs of legs wholly yellow 



G. pallidipes Austen 



CO. Rays of the arista not plumose; only one or two stemopleurals; base of 

 the media not strongly bowed down ; apical cell opens at or very near 

 the apex of the wing, 

 d. Vein R4+6 without setae at the base; palpi about as long as the pro- 

 boscis, 

 e. Arista pectinate (i. e. rays on one side only), the rays often undtdate; 

 two yellow stemopleurals often difficult to detect; vein M 1+2 

 only slightly bent, the apical cell hence wide open. The horn fly, 

 H. irritans {=Lyperosia serrata) and related species. Widely dis- 

 tributed (figs. 167, 168) Haematobia R. D. not B. B. 



165. Glossina morsitans. (x4.) After Austen. 



ee. Arista also with rays below; vein Mi-1-2 more strongly bent, the 

 apical cell hence less widely open. 

 f. Palpi strongly spatulate at the tips, lower rays of the arista about 



six in number, B . sanguinolentus . South Asia 



Bdellolarynx Austen 



ff. Palpi feebly spatulate; apical cell of the wing narrowly open 

 slightly before the tip; stemopleurals black, anterior bristle 



sometimes absent. H . atripalpis . Europe 



Haematobosca Bezzi 



dd. Vein R4+5 with setiE at the base.* 



'^Pachytnyia Macq. is closely related to Stomoxys. It differs in having the arista rayed both 

 above and below. P. vexans, Brazil. 



