Key to the genera of the subfamily Mesitiinae from China (modified after Azevedo et al. 2018)

1. Female ............................................................................................................................................... 2

– Male .................................................................................................................................................. 3

2. Median mesonotal sulcus well developed on apical half of mesoscutum (Fig. 12E); anterior ocellus usually entirely anterior to imaginary top line of eyes in antero-dorsal view (Fig. 10B) ............................................................................................... Sulcomesitius Móczár, 1970

– Median mesonotal sulcus absent, mesoscutum broadly impressed in middle of apical half (Figs 6E, 7E); anterior ocellus usually crossing imaginary top line of eyes in antero-dorsal view (Fig. 5B) ............................................................................................... Heterocoelia Dahlbom, 1854

3. PPP absent ................................................................................................ Metrionotus Móczár, 1970

– PPP present ....................................................................................................................................... 4

4. Posterior margin of hypopygium incurved with branches broad and short, less than 0.3× length of hypopygium (Figs 3H, 8G, 9H) ........................................................................................................ 5

– Posterior margin of hypopygium deeply incurved with branches narrow and long, usually more than 0.4 × length of hypopygium (Figs 11H, 13H, 14H) .......................................................................... 6

5. Antennal setae long, longer than width of flagellomere (Figs 8B, 9C); aedeagus usually with apical sickle process ......................................................................................... Incertosulcus Móczár, 1970

– Antennal setae short, about one-third width of flagellomere (Fig. 3C); aedeagus without apical sickle process ................................................................................................. Heterocoelia Dahlbom, 1854

6. Dorsal pronotal area usually with anterolateral corner distinctly projected (Fig. 16D); basal part of hypopygium with lateral margin distinctly incurved and posterior branches of hypopygium usually filamentary (Figs 17I, 18I) .................................................................... Zimankos Argaman, 2003

– Dorsal pronotal area usually with anterolateral corner weakly projected (Fig. 11D); basal part of hypopygium with lateral margin usually parallel and posterior branches of hypopygium lobose (Fig. 15H) .............................................................................................. Sulcomesitius Móczár, 1970