618 
DlPTELiA. 
generally not reaching as far as the middle of 
the wing. 
1. 2nd Basal and Discal cells not separated by a 
cross-vein. 
Small generally yellowish or black flies, fre¬ 
quently caught by sweeping grass. Sub-costa 
absent. Fronto-orbital bristles and vibrissae 
usually absent ; anal cell absent 
Small often greenish-grey or brown flies found 
on or near water ; predaceous, mouth-opening 
often very large. No vibrissae, and anal cell 
absent or indistinct. Fr onto-orbitals frequently 
present. Sub-costa absent 
2. 2nd Basal and Discal cells nearly always 
separated by a cross-vein. 
Small often grey or silvery flies, as a rule 
vibrissae present. Aristal hairs never very 
long. 2nd basal and anal cell often very 
small, but distinct, cross-veins generally near 
together 
Often fair-sized fruit-flies, partly coloured yellow, 
wings with dark marks or spots. Lower fronto- 
orbitals present. Sub-costa turning up sharply 
and ending indistinctly before joining the 
costa. No vibriss3e or pre-apical bristles. Anal 
cell very often drawn out into a long point. 
Ovipositor rather long 
Not very small flies. Abdomen generally black, 
long, oval in shape. Subcosta more or less 
fused with R, : Antennae sometimes long. 
Vibrissje absent. Anal cell not drawn out into 
a point 
B.—Sub-costa present, distinct, ending distinctly in 
costa. R, generally reaches at least as far as 
the middle point of the costa. 
1. Vibrissae absent. 
Chloropids. 
Ephydrids. 
Agromyzids. 
(Geomyzids). 
Trypetids. 
Psilids. 
