Key to species of the subgenus Separatatus Chen & Wu

1. Basal part of pterostigma long and parallel-sided; vein r close to apex of pterostigma; [vein 3-SR of fore wing about 2.9 × longer than vein r; hind femur ca 2.7 × longer than wide]; China (Yunnan, Hainan)................................................................................................... S. parallelus Zhu, van Achterberg & Chen, 2017

- Basal part of pterostigma comparatively short and elliptical; vein r more removed from apex of pterostigma (Fig. 18A); [vein 3-SR of fore wing ca 3.0 × longer than vein r, also pterostigma more robust]...................................... 2

2. Mandible hardly emarginated between first and second teeth of mandible, ventral lobe of mandible small; medio-posterior depression of mesoscutum elongate and about half as long as mesoscutum medially; body blackish or reddish black; precoxal sulcus present anteriorly (Fig. 18C); legs partly dark brown or reddish black (Fig. 17)............................... 3

- Emargination between first and second teeth of mandible distinct; ventral lobe of mandible medium-sized; medio-posterior depression of mesoscutum small and round; body reddish brown or yellowish brown; precoxal sulcus absent anteriorly; legs yellow............................................................................................. 4

3. Pterostigma more widened medially, about 3.5 × longer than wide (Fig. 18A); width of head 1.6 × its lateral length; scutellar sulcus deep and narrow, with one median carina and four short longitudinal carinae and 4.4 × wider than its maximum length (Fig. 18D); [vein 1-SR+M of fore wing nearly straight; vein cu-a of fore wing distinctly postfurcal] … S. platystigma sp. nov.

- Pterostigma less widened medially, about 3.8 × longer than wide; width of head 2.2 × its lateral length; scutellar sulcus wide, with two carinae and 3.3 × wider than its maximum length; [vein 1-SR+M of fore wing slightly sinuate basally; vein cu-a of fore wing slightly postfurcal]..................................... S. megagnathus Sohn & van Achterberg, 2022

4. Vein r-m of fore wing weakly inclivous; first flagellomere (including annellus) 0.9 × as long as second flagellomere; propodeum with a quadrilateral areola, entirely irregularly wrinkled; [length of first tergite 1.1 × longer than its apical width; second tergite with striation medially; hind femur of ♀ rather inflated, ca 3.0 × longer than wide]; China (Yunnan).............................................................................................. S. carinatus Chen & Wu, 1994

- Vein r-m of fore wing strongly inclivous; first flagellomere (including annellus) 0.7 × as long as second flagellomere; propodeum either with a bell-shaped areola or with an irregular areola medially; [length of first tergite 0.8 or 1.2 × its apical width; second tergite smooth or with less striation medially].............................................................. 5

5. Head and second flagellomere yellow; hind femur of ♀ ca 3.5 × longer than wide; length of first tergite 0.7 × its apical width; propodeum with a bell-shaped areola and almost smooth; West Malaysia .................. S. malaysiae (Fischer, 2006)

- Head and second flagellomere mainly dark brown; hind femur of ♀ ca 2.6 × longer than wide; length of first tergite 1.2 × its apical width; propodeum with a bell-shaped areola and almost smooth; Thailand ............... S. xuexincheni Yao, 2018