Key to the Metrocoris lituratus group species (based on apterous males)
1. Fore femur with a constriction in the middle, basal half slightly thicker than apical half.............................. 2
- No constriction in the middle of fore femur but with a subapical indentation and a single apical tooth................... 6
2. Constriction in middle of fore femur marked by a tooth-like edge; basal edge of subapical indentation also tooth-like...... 3
- Neither the edge of median constriction of fore femur nor the edge of subapical indentation tooth-like................................................................................................ M. constrictus Chen & Nieser
3. Paramere with hooked tip............................................................................... 4
- Paramere with blunt tip................................................................................. 5
4. Paramere apically with a small hook curved upward............................................ M. lituratus (Stål)
- Paramere apically birdhead-shaped............................................................... M. xiei Chen
5. Apex of paramere truncate........................................................... M. esakii Chen & Nieser
- Outer edge of paramere with a distinct sharp turn, apex truncate........................ .. M. cantonensis Chen & Nieser
6. Blade of paramere laterally with angular projection in the middle (Figs. 63–66)....................................7
- Blade of paramere laterally without projection in the middle (Figs. 59–62)....................................... 10
7. Body size relatively small (5.85–6.05); male proctiger laterally without a pair of blackish dots (Fig. 55).. M. astictus sp. nov.
- Body size relatively large (more than 6.62); male proctiger laterally with a pair of blackish dots (Fig. 56–58)............. 8
8. Paramere stout and triangularly curved upwards (Figs. 66, 83); accessory lateral sclerites of endosoma relatively thick in dorsal view (Figs. 71, 81)....................................................................... M. zhengi sp. nov.
- Paramere laterally not triangle-shaped; accessory lateral sclerites of endosoma relatively thin in dorsal view.............. 9
9. Paramere laterally with distinctly angular projection, apex slightly curved upward (Figs. 64, 77)...... M. falciformis sp. nov.
- Paramere with small projection, apex without curving (Figs. 65, 80).......................... M. guizhouensis sp. nov.
10. Abdominal tergite VII strongly developed, paramere apically tapering......................... M. heineri Chen & Zettel
- Abdominal tergite VII slightly developed, paramere apically slightly extended.................................... 11
11. Paramere comparatively smaller.................................................. M. sichuanensis Chen & Nieser
- Paramere comparatively large...........................................................................12
12. Apex of paramere round, without projection................................................. M. cylindricus Chen
- Apex of paramere blunt, inner side with a small hook-like projection.............................. M. hubeiensis Chen