Key to species of Quedius (Microsaurus) mukuensis group

1. Wings reduced, only slightly longer than elytra; abdominal tergite VII without or only with inconspicuous whitish apical seam of palisade setae....................................................................... Q. medius sp. nov.

- Wings fully developed; abdominal tergite VII with distinct whitish apical seam of palisade setae..................... 2

2. Median lobe of aedeagus with two processes at apex facing parameral side (Figs. 9 E; 9-1G)......................... 3

- Median lobe of aedeagus with one process at apex facing parameral side (e.g., Figs. 2 E; 2-1G)....................... 5

3. Size distinctly smaller, shorter than 6.5 mm; body bicolored, with elytra reddish brown, other parts black.................................................................................................... Q. kabateki Smetana

- Size distinctly larger, longer than 6.5 mm; body unicolored, blackish brown to black............................... 4

4. Protonum with three setiferous punctures in each dorsal and sublateral row; male sternite VIII with 2–3 long setae on each side

................................................................................. Q. mukuensis Bernhauer - Protonum with four setiferous punctures in each dorsal and sublateral row (Fig. 9 B); male sternite VIII with 3–4 long setae on each side (Fig. 9-1 A).................................................................... Q. nireus Smetana

5. Head with additional setiferous punctures anteriad of posterior frontal setiferous puncture (Figs. 7 A; 8A; 9A)........... 6

- Head without additional setiferous punctures anteriad of posterior frontal setiferous puncture (e.g., Fig. 4 A)........... 10

6. Male sternite VIII with six long setae on each side; aedeagus with apex of paramere protruding beyond that of median lobe.................................................................................... Q. xiaoae Zheng et al.

- Male sternite VIII with fewer than six long setae on each side; aedeagus with apex of paramere not reaching that of median lobe............................................................................................... 7

7. Median lobe of aedeagus with apical portion strongly dilated laterally into triangular apex (Figs. 7 E; 7-1G).................................................................................................... Q. gongga Smetana

- Median lobe of aedeagus with apical portion narrow, nearly parallel-sided, not apreciably dilated laterally, apex narrowly arcu- ate (e.g., Figs. 8 E; 8-1G).............................................................................. 8

8. Paramere of aedeagus with some sensory peg setae situated above level of subapical setae insertion points (Figs. 8 D; 8-1F)...................................................................................... Q. haemon Smetana

- Paramere of aedeagus with sensory peg setae far below apex, all below level of subapical setae insertion points......... 9

9. Male sternite VIII with four long setae on each side, with medioapical emargination deeper; median lobe of aedeagus with small tooth-shaped process at apex facing parameral side......................................... Q. haan Smetana

- Male sternite VIII with five long setae on each side, with medioapical emargination shallower; median lobe of aedeagus with distinctly developed long medial carina at apex facing parameral side.............................. Q. raan Smetana

10. Paramere of aedeagus with sensory peg setae not only forming two groups, but also with one other peg seta on each side situ- ated far below them (Figs. 4 D; 4-1F)........................................................ Q. purus sp. nov.

- Paramere of aedeagus with sensory peg setae only forming two groups (e.g., Figs. 5 D; 5-1F)....................... 11

11. Paramere of aedeagus relatively wide, covering entire apical portion of median lobe except for very apex..................................................................................................... Q. epytus Smetana

- Paramere of aedeagus relatively narrow, only covering part of apical portion of median lobe........................ 12

12. Male sternite VIII with three long setae on each side....................................................... 13

- Male sternite VIII with four long setae on each side........................................................ 14

13. Paramere of aedeagus relatively longer, with apex almost reaching that of median lobe, with about three sensory peg setae on its underside............................................................................ Q. tzwu Smetana

- Paramere of aedeagus relatively shorter, with apex distinctly not reaching that of median lobe, with about six sensory peg setae on its underside........................................................................ Q. antoni Smetana

14. Paramere of aedeagus straight and parallel-sided (Figs. 5 D; 5-1F)................................. Q. rectus sp. nov.

- Paramere of aedeagus slightly curved or not parallel-sided................................................... 15

15. Paramere of aedeagus straight, gradually narrowed to apex (Figs. 6 D; 6-1F)......................................................................................................................... Q. guoi Zheng & Zheng

- Paramere of aedeagus slightly curved toward left, nearly parallel-sided (Figs. 2 D; 2-1F)............ Q. indigestus sp. nov.