DIPTERA 



829 



SUBSERIES A — THE ANOMALOUS BRACHYCER^ 



In the families constituting this subseries the antenna consist of 

 five or more segments; but those beyond the second, the flagellum, 

 are usually more or less consolidated. In some cases the antennae do 

 not differ markedly in form from those of certain Anomalous Ne- 

 mocera; but the Brachycera are sharply distinguished from the Ne- 

 moceraby the palpi being porrect and only one or two- jointed and b}' 

 the fact that the anal cell is either closed or narrowed towards the 

 margin of the wing. In this subseries the head and thorax are not 

 furnished with strong bristles and the empodia are pulvilli-form. 



Family TABANID^ 



The Horse-Flies 



The horse-flies are well-known pests of 

 stock, and are often extremely annoying to 

 man. They appear in siunmer, are common 

 in woods, and are most abundant in the hottest 

 weather. 



In this family the flagellum of the antennae 



is composed of from four to eight, more or less 



^f' ^"yy^t closely consolidated segments and is never Fig. 1055.- 



nus. furnished with a distinct style or arista (Figs. Antenna 



1054, 1055). The wing-veins (Fig. 1056) are oiChry- 



evenly distributed over the wing, as the 



branches of vein R are not crowded together as in the following 



family; the costal vein is continued as an ambient vein which extends 



Fig. 1054.— 



Antenna 



Fig. 1056. — Wing of Tabanus. 



completely around the wing; the alulets are large, in other Anomalous 

 Brachycera they are small or vestigial. 



The flight of these flies is very powerful, they are able to outstrip 

 the swiftest horse. The males feed on the nectar of flowers and on 

 sweet sap. The mouth-parts of the female are fitted for piercing the, 



