Key to species of genus Ommatissus

1. Frons without dark spots................................................................................ 2

- Frons with distinct dark spots............................................................................ 3

2. Periandrium with two long processes which exceed length of aedeagus (see Asche & Wilson 1989: 139, Fig. 35).............................................................................................. O. bimaculatus Muir

- Periandrium without any process, ring-like (see Asche & Wilson 1989: 144, Fig. 52).................................................................................................. O. (Opatissus) vietnamicus Asche & Wilson

3. Frons with more than two dark markings, one pair next to vertex, other pair next to postclypeal suture.................. 4

- Frons with only one pair of dark markings next to vertex...................................................... 5

4. Frons with a pair of circle spots next to postclypeal suture (see Asche & Wilson 1989: 133, Figs 17, 18).............................................................................................. O. natalensis Asche & Wilson

- Frons with a pair of strip markings next to postclypeal suture (Figs 12, 47)..................... O. trimaculatus sp. nov.

5. Processes of periandrium very long, reaching or surpassing to tip of aedeagus...................................... 6

- Processes of periandrium short, not reaching to tip of aedeagus................................................. 8

6. Processes of periandrium forming an inverse S; aedeagus forming an inverse S (see Asche & Wilson 1989:141, Figs 41, 43–44)................................................................................ O. lofouensis Muir

- Processes of periandrium forming a bridge; aedeagus straight, tubular............................................ 7

7. Frons with a reverse pyriform dark patch next to vertex (Fig. 15).................................. O. fuscus sp. nov.

- Frons with a pair of circle spots next to vertex (Fig. 26)........................................ O. lateralis sp. nov.

8. Periandrium with 3 caudad or ventrocaudad directed processes................................................. 9

- Periandrium with fewer than 3 caudad or ventrocaudad directed processes........................................ 11

9. Aedeagus without subapical tooth or spine................................................................. 10

- Aedeagus with distinct subapical ventral tooth (see Asche & Wilson 1989: 139, Fig. 40)............. O. chinsanensis Muir

10. Aedeagus with end part fine, acerate and curved (see Asche 1994: 225, Figs 5–6)................... O. bourgoini Asche

- Aedeagus with end part traverse and straight (see Asche & Wilson 1989: 144, Fig. 45)............... O. lybicus Bergevin

11. Postclypeus dark brown, darker than frons, pale only vertically on midline.......................................12

- Postclypeus light brown not distinctly darker than frons...................................................... 13

12. Aedeagus not distinctly longer than anal tube, gonostyli apically rounded (see Asche & Wilson 1989: 139, Fig. 34)........................................................................................... O. alpinus Linnavuori

- Aedeagus conspicuously longer than anal tube, gonostyli distally pointed (see Asche & Wilson 1989: 141, Fig. 42).................................................................................... O. kamerunus Asche & Wilson

13. Aedeagus straight, short, not exceeding anal tube; periandrium ventrally projected into an acute tip (see Asche & Wilson 1989: 144, Fig. 51)...................................................................... O. tumidulus Linnavuori

- Aedeagus longer than anal tube, curved.................................................................. 14

14. Aedeagus about 1.3 times longer than anal tube, slightly curved dorsad (see Asche & Wilson 1989: 139, Figs 36–38)............................................................................................ O. binotatus Fieber

- Aedeagus about 4 times longer than anal tube, strongly curved dorsad (see Asche & Wilson 1989: 144, Fig. 47)........................................................................................ O. magribus Asche & Wilson