4 BItACHYCERA. 



in the 4th vein ; 3rd vein simple except in a few 

 Empid^e ; posterior cross-vein quite absent ; 

 posterior cells apparently never more than four, 

 but usually less ; wing-veins altogether few and 

 simple ; alula obsolete. Face bare or only 

 slightly pubescent in the Micuophona, but 

 with peristomal bristles in Lonchopteridje and 

 side or genal bristles in Pkohidm, but with 

 no face beard or pubescence as in Asilid^e. 

 Cephalic bristles usually strongly developed. 

 Species always small and distinctly chseto- 

 phorous 5. 



3. Aerial species, almost always clothed with dense 



furry pubescence. Legs thin and only suitable 

 for alighting, and consequently armed with little 

 more than spicules (not true bristles) on the 

 femora and tibiae. Eyes nearly always touching 

 in the <5 (holoptic) and never bulged out because 



of a sunken vertex. . . Tromoptera. 



Pedestrian species, usually armed with strong bristles 

 and only occasionally [La/phria, Isopogon, etc.) 

 clothed with dense coarse pubescence ; or (Der- 

 matina) bare of both pubescence and bristles. 

 Legs strong, usually armed with strong bristles 

 on at least the tibiae and tarsi. Eyes almost 

 always widely separated in both sexes (dichoptic), 

 and frequently bulging out because of the deeply 

 sunken vertex 4. 



4. Erernochastous species in the sense that there are 



no strong bristles on any part of the thorax or 



scutellum Dermatina. 



Chastophorous species in the sense that there are 

 strong and usually numerous bristles on the 

 thorax, scutellum, and legs, or at least on the 

 sides of the metanotum, except in the few cases 

 in which dense coarse pubescence is substituted. Energopoda. 



5. Wing-veins (including cross-veins) fairly normal, or 



else the 2nd and 3rd veins extended almost to 

 the wing-tip. Antennas with three (or rarely 

 two) joints obvious, besides any style or arista. . G. 



"Wing-veins extremely abnormal and quite distinct 

 from those of any other Diptera (except Aspistes 

 in the Bibionidje) ; anterior veins up to the 

 3rd vein strong and conspicuous, running into 

 the basal half of the costa, but the subsequent 

 veins very faint and incomplete and abnormally 

 directed ; 4th, 5th, and anal veins very difficult 

 to trace. Palpi porrect, not jointed. Eyes 

 widely and equally separated in both sexes. 

 Antennae apparently composed of one large joint, 

 which bears a very long apical or dorsal arista. 

 Hind legs long and the femora flattened Hypocera. 



Win<j rounded at the tip ; venation fairly normal, 

 with the 2nd vein ending considerably before 

 the wing-tip, and with at least one apparent 

 cross-vein well out towards the middle of the 

 wing, causing the discal cell to be present even if 



