Key to Mycomya species of the South-East Asian islands

1. Coxa 2 with a spur (Väisänen 1984a: figs. 377, 436, 445, 597, 825)............................................. 2

- Coxa 2 without a spur................................................................................. 3

2. Abdominal tergites entirely dark or light, or dark with paler posterior margins; abdominal tergite 8 with setae; tergal part of male hypopygium without a fork-like median structure; ocellar prominence not distinctly darker than posterior parts of head …............................................................ subgenus Mycomya s. str.: M. occultans (Winnertz)

- Abdominal tergites yellow with dark posterior margins; abdominal tergite 8 bare; tergal part of male hypopygium with a forklike median structure (e.g. Fig. 7 D); ocellar prominence usually distinctly darker than posterior parts of head........................................................................ subgenus Calomycomya Väisänen: M. shimai sp. n.

3. Sternal synsclerite of male hypopygium with long, wide, sternal lateral appendages (extending towards tergal part of hypopygium in lateral view; e.g. Figs. 2 C, 4C, 5C, 8C); tergal part of hypopygium without lateral appendages (e.g. Figs. 2 A, 4A, 5A)....................................................................... .. (subgenus Cymomya Väisänen) ... 4

- Sternal synsclerite without large lateral appendages (e.g. Figs. 1 B, 3B, 6B); tergal part with lateral appendages (e.g. Figs. 1 A, 1D, 3A, 3D, 6A)....................................................... (subgenus Mycomyopsis Väisänen)...7

4. Sternal lateral appendage very long, wide and rounded, its subapical part much wider than its basal part (Fig. 5 C)............................................................................................... M. paraklossi sp. n.

- Sternal lateral appendage smaller, its subapical part is slightly narrower or about as wide as its basal part (Figs. 2 C, 4C, 8C)..................................................................................................... 5

5. Sternal lateral appendage relatively long, apically rounded, its subapical part is about as wide as its basal part, densely setose; long setae covering at least apical ½ of sternal synsclerite (Fig. 2 C); wing vein Sc ending in R1; M and Cu bare; wing length 2.5 mm ................................................................................ M. klossi Edwards

- Sternal lateral appendage short, tapering towards apex, sparsely setose; long setae covering apical 1/3 of sternal synsclerite

(Figs. 4 C, 8C); Sc ending in C or R1; M and Cu bare or with small setae; wing length 4.0– 4.5 mm ..................... 6 6. Sc ending in C; M and Cu bare; small cell and apex of wing weakly infuscated; sternal lateral appendage apically blunt, triangular, tapering towards apex (Fig. 8 C).......................................................... M. yatai sp. n.

- Sc ending in R1; M and Cu with some small setae; wing hyaline; sternal lateral appendage rounded, tapering towards apex (Fig. 4 C)................................................................................. M. nakanishii n. sp.

7. Gonostylus short and wide, about 2x as long as its width, with a spur in its middle part (Fig. 3 E)...... M. minutata Edwards

- Gonostylus long and slender, 5– 6 x as long as its width, without a spur (Figs. 1 E, 6E).............................. 8

8. Outer tergal combs of tergal part of hypopygium both with about 5 spines (Fig. 6 A); basal and middle part of tergal lateral appendage bare (Figs. 6 C–D)................................................................ M. pongo sp. n.

- Outer tergal combs of tergal part of hypopygium both with about 10 spines (Fig. 1 A); middle part of tergal lateral appendage sparsely setose, without distinct bare area (Figs 1 C–D).......................................... M. apoensis sp. n.