7,S PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiii. . 



TABLE OF (iENERA. 



Basal abdominal segment ivilliout a transverse impression 2 



Basal abdominal segment wiiJi a transverse impression. 



Front wings unlhout an areolet; metathorax short, 'with an apical transverse 

 carina and a basal area, the spiracles small, round; transverse 

 median nervure in hind wings broken below the middle. 



(596) Bassus Gravenhorst. 



2. Front wings niili an areolet 5 



Front wings without an areolet. 



Face finely shagreened, alutaceous or coriaceous 4 



Face entirely smooth, shining. 



Antennpe 20-jointed or less 3 



Antennte more than 20-jointed. 



Clypens separated from the face; metathorax areolated; transverse 

 median nervure in hind wings broken at or near the middle. 



(597) Promethcs Forster. 



3. Clypeus very broad, the foveie of same wider from each other than the distance 



to the eye margin (598) BioUapsis Forster. 



(^ Trichomastix Vollenhoven. ) 



Clypeus 7wt very broad, the fovete of same not wider from each other than the 



distance to the eye margin (599) Liopsis Forster. 



4. Metathorax not short, more or less areolated, the areola and the basal area 



usually confluent; first recurrent nervure, or the disco-cubital 

 nervure, strongly curved, not angularly broken; transverse 

 median nervure in hind wings broken at alwut the l^asal third. 



(600) Zootrej)hcs Forster. 

 Metathorax short, exareolated; disco-cubital nervure angularly broken and 

 usually with a stump of a vein present; transverse median nerv- 

 ure in hind M-ings very obtusely angularly broken below the 

 middle (601) Syrphodonns Forster. 



5. Metathorax not at all areolated 6 



Metathorax more or less areolated, or at least with a basal median area. 



Metanotum rather long with two parallel longitudinal carina^ the space 

 between narrow, the areola and the basal area usually confluent; 

 basal joint of hind tarsi elongate, the longer spur of the hind 

 tibife short, not nearly half the length of the basal joint. 



(602) Phthorima Forster. 

 Metanotum shorter, the areola broad, hexagonal; longer spur of hind 

 tibite fully half the length of the basal joint of tarsi. 



(603) Aniaropliron Forster. . 



6. Second abdominal segment 'with two short median carina3 at base, the dorsal 



carinaa of the first segment strongly convergent posteriorly, the 

 ventral cavity of same notched; hind legs elongate; disco- 

 cubital nervure angularly bent near the middle, the transverse 

 median nervure not interstitial, the submedian cell longer than 



the median ( 604) Enizemum F(')rster. 



Second abdnminal segment without middle carinse at base, the first without 

 carinse, or if present very short and widely separated, the ven- 

 tral cavity of same not notched; transverse median nervure 

 interstitial, or very nearly, with the basal nervure. 



(605) Homotropus Forster. 



