Diptera. 65 



28. Fourth vein ending before the wing-tip; at least the scutellum bristly; antennae 



with a very short style; eyes separated; palpi broadened at tip. (Apiocera, 



Rhaphiomydas) APIOCERID^ 



Fourth vein ending beyond the tip of the wing; body usually furry rather than 

 bristly; palpi not broadened apically. (Thereva, Psilocephala, Tabiida) 

 (PI. 12. fig. 293) THEREVIDiE 



29. Proboscis long and thin; body usually furry and stout though rarely (Sys- 



tropus) extremely slender and bare; a small style usually present; fourth 

 vein ending beyond tip of the wing. (Anthrax, Exoprosopa, Bombylius, 

 Geron, Systropus.) (PI. 11, fig. 249; PI. 12, figs. 265, 294) . . BOMBYLIID^ 

 Proboscis hidden; body bare; antennae without a style; fourth vein ending at 

 the tip of the wing. (Scenopinus, Pseudatrichla) (PI. 11, fig. 248). 



{OMPHRALID.E) SCENOPINID^ 



SO. Body without bristles; fourth vein curving forward, neuration complex, pre- 



furca (the stalk of the second and third veins) short; antennae with a clubbed 



style; proboscis with fleshy expanded tip, palpi vestigial. (Mydas, Lepto- 



mydas) (PI. 12, fig. 298) {MYDASIDM) MYDAID^ 



Body usually with bristles, face bearded; fourth vein not curving forward, 

 neuration normal, prefurca long; proboscis adapted for piercing, not fleshy, 

 palpi usually prominent. Robber-flies. (Leptogaster, Cyrtopogon, Laph- 

 ria, Erax, Proctacanthus) (PI. 12, fig. 264) ASILID^ 



31. No frontal suture; anal crossvein usually reflexed; when the anal cell is pointed 



the arista is terminal and the calypteres and alula are not prominent . . 32 

 If the anal crossvein is reflexed a frontal suture is evident, if the frontal lunule 

 is obscure the anal cell is longer than the second basal cell; arista almost 

 always dorsal; calypteres and alula usually pronounced. (CYCLOR- 

 RHAPHA) 35 



32. Neuration fairly normal, without faint oblique veins; antennae evidently two- 



or three-jointed 33 



Wings, when present, with several stout anterior veins running into the costa 

 and other weak ones obliquely extending across the wing; antennae placed 

 low, apparently single-jointed and with a long arista; hind legs long, their 

 femora compressed; small, hunchbacked, quick running flies. (Dohmi- 

 phora, Phora, Hypocera, Aphiochaeta.) (PI. 11, fig. 250) PHORID^E 



33. Wings rounded at the tip, second vein ending considerably, before the wing- 



tip, crossveins present; oral bristles absent; eyes of males often meeting; 

 face usually narrow; predaceous species. (Microphona, Orthogenta.) . . 34 

 Wings pointed, no crossveins except at the base, second basal cell short, second 

 vein ending almost at the tip of the wing; face with oral vibrissae; eyes sep- 

 arated. (Acroptera) (Lonchoptera.) (PI. 11, fig. 254; PI. 12, fig. 278). 



{MUSIDORIDM) LONCHOPTERID^ 



54. At least one basal cell evident, discal cell usually separate from the second 



basal cell; calypteres small; proboscis usually rigid; antennal style or arista 



usually terminal; abdomen typically with seven segments, male genitalia 



never inflexed; color almost never metallic; third vein sometimes forked. 



