Empididae. 251 



5. Tachydromiinae. 

 Eyes generally separated above the antennæ in both sexes; below 

 the antennæ either likewise separated {Chersodromia, Tachydromia), 

 or they are here touching in both sexes, and in the latter case either 

 the facets in the front part of the eye enlarged, likewise in both 

 sexes {Stilpon, TacJiypeza , Tachista) or all facets of equal size, 

 {Drapetis (eyes not quite touching), Elaphropeza). Rarely the eyes 

 are touching above the antennæ in both sexes, and then the facets 

 in the front part are enlarged {Symhallophthalmus). Sometimes the 

 eyes are short-haired or microscopically haired {Drapetis, Stilpon, 

 Chersodromia, Elaphropeza). Antennæ four- to five-jointed, terminating 

 with a two-jointed or unjointed arista, which is generally apical, 

 rarely {Stilpon) dorsal (apparently). Proboscis short, sometimes curved 

 inwards towards the sternum, No maxillæ; maxillary palpi one-jointed. 

 Metapleura bare, or with very short hairs {Drapetis). Legs shorter or 

 longer; sometimes the front femora thickened, sometimes both front 

 and middle femora, especially the latter, and the middle tibiæ with 

 an apical spine; the pair or pairs of legs in question are then speci- 

 ally armed and raptorial. Wings with the cubital vein unforked; the 

 discai vein likewise unforked; three posterior cells and no discai cell. 

 Basal cells somewhat large, of equal iength, or the second longer 

 than the first; anal cell present and shorter than the basal cells, or 

 wanting, and in accordance herewith the anal vein present or wanting; 

 when present the vein is however weak; the lower branch of the postical 

 vein present or absent. Axillary lobe small or somewhat developed, 

 No alula. No stigma. 



Table of Genera. 



1. Anal cell absent 2, 



— Anal cell present, anal vein more or less weak, but 

 distinct; basal cells of about equal Iength 7. 



2. First basal cell shorter than the second 3. 



— First basal cell as long as the second 25. Chersodromia. 



3. Legs rather short; body short and robust; colour 

 black or gray; wings without markings 4. 



— Legs somewhat slender; body not robust; wings with 

 dark markings, or at all events some veins seamed, 



or when hyaline the thorax is yellow 5. 



4. Frons triangular; arista terminal 20. Drapetis. 



— Frons with parallel margins; arista dorsal 21. Stilpon. 



5. Third antennal joint short, ovate; front femora con- 

 siderably thickened; wings more or less dark marked; 

 thorax black 6. 



— Third antennal joint a little longer, conical; front 



femora not thickened; wings hyaline; thorax yellow 24. Elaphropeza. 



