Key to males for species of the Lispe caesia -group from Palaearctic and adjacent regions

1. Antennal postpedicel entirely orange (Fig. 14 B) ·.......................................... L. flavicornis Stein, 1909

- Antennal postpedicel grey or black........................................................................ 2

2. Apex of wing with cloud (Fig. 27 E)................................................. L. patellitarsis Becker, 1914

- Wing entirely transparent............................................................................... 3

3. Fronto-orbital plate, frontal vitta and frontal triangle without obvious boundary (Fig. 5 B).................................................................................................. L. aquamarina Shinonaga & Kano, 1983

- Fronto-orbital plate, frontal vitta and frontal triangle with obvious boundary....................................... 4

4. Mid tibia with 2 willowleaf-like ventral spines on apex (Fig. 20 B)......... L. lanceoseta Wang & Fan, in Wang et al., 1981

- Mid tibia without specialized ventral spines on apex.......................................................... 5

5. Hind tibia with dense and long ventral setae................................................................. 6

- Hind tibia with 1 long submedian pv or without long ventral setae on distal half.................................... 7

6. Hind tibia with long ventral tuft on distal 1/3 and 1 av row (Fig. 19 D)................... · L. hirsutipes Mou in Fan, 1992

- Hind tibia without tuft but with ununiformly-spaced setulae rows on each surface and different-sized developed ventral setae on distal half of av and pv surfaces (Fig. 17 A).......................................... L. halophora Becker, 1903

7. Abdominal tergites without patches (Fig. 23 D); antenna very small, postpedicel about 1.5–1.7 times as long as broad (Fig. 23 B); vibrissa absent (Fig. 23 C).................................................... L. leucocephala Loew, 1856

- Abdominal tergites with patches; antenna regular-sized, postpedicel more than 2.8 times as long as broad; vibrissa present.. 8

8. Both abdominal tergites 3 and 4 with large obvious patches (Figs. 12E; 26C) ·..................................... · 9

- Abdominal tergite 3 with small faint patches, tergite 4 with large obvious patches (Figs. 8 E; 10E).................... · 10

9. Frontal vitta with silvery grey pollinosity (Fig. 12C) ·.................................... L. candicans Kowarz, 1892

- Frontal vitta with golden pollinosity (Fig. 26 B)............................. · L. palawanensis Shinonaga & Kano, 1989

10. Frontal vitta, fronto-orbital plate and parafacial with golden pollinosity; palpi silvery grey (Fig. 8 B)................................................................................................. L. caesia caesia Meigen, 1826

- Frontal vitta, fronto-orbital plate and parafacial with silvery grey pollinosity; palpi yellow (Fig. 10 B)............................................................................................. L. caesia microchaeta Séguy, 1940