Key to species of Strongylophthalmyia ustulata group from China

1 Mesonotum yellowish brown with blackish brown longitudinal band along midline (Figs 9, 10); abdominal tergites mostly yellow with dark brown median patches (Figs 9, 10)..................................... S. flavimarginata sp. nov.

- Mesonotum entirely black (Figs 1–4, 15, 16, 21); abdominal tergites mostly dark brown to black (Figs 2–4, 15, 16, 21).... 2

2 Wing with indistinct dark suffusion at apex (Fig. 33)...................................... S. ustulata (Zetterstedt)

- Wing with distinct dark suffusion or patch at apex and median transverse band (Figs 30, 32).......................... 3

3 Postpronotum and propleuron yellow (Figs 1, 2)........................................ S. bifasciata Yang & Wang

- Postpronotum and propleuron entirely black (Figs 3, 4, 15, 16)................................................. 4

4 Antennal arista blackish brown (Fig. 26); apical dark patch and median transverse band on wing much darker in cell r 2+3 than their remaining parts (Fig. 30); fore femur yellow, lacking dark markings (Figs 3, 4)................. S. elongata sp. nov.

- Antennal arista yellowish brown with apical third blackish brown (Fig. 28); apical dark patch and median transverse band on wing not darkened in cell r 2+3 than their remaining parts (Fig. 32); fore femur yellow, with large blackish brown spot dorsal in apical third (Figs 15, 16).................................................................. S. sivelli sp. nov.