Key to genera of Usiinae from China

1. Flagellum with an articulated spine-like second flagellomere in addition to a stylus; discal cell open or closed by crossvein m-m; narrow bodied flies ........................................................................................................ Apolysis Loew

- Flagellum without a second flagellomere; discal cell always closed by crossvein m-m; compact bee-like flies ....... 2

2. Oral margin narrow in frontal view, gena almost non-existent or extremely narrow, usually only represented by a ridge between oral-genal cup and inner eye margin; eyes of males dichoptic ......................................... Usia Latreille

- Oral margin much broader, gena present between inner eye margin and oral-genal cup; eyes of males usually holoptic ................................................................................................................................................. Parageron Paramonov