304 Hominoxious Arthropods 
ff. Tarsi of the first and second pairs of legs wholly yellow. 
. G. pallidipes Austen 
cc. 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+5 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 undulate; 
two yellow stemopleurals often difficult to detect; vein M 1-1-2 
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. (X 4 .) After Austen. 
ee. Arista also with rays below; vein M1+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 R4A5 with setae at the base.* 
*Pachymyia Macq. is closely related to Stomoxys. It differs in having the arista rayed both 
above and below. P. vexans, Brazil. 
