Key to Stenus species of the cirrus group

1 Paraglossae oval ( cirrus -complex) ............................................................................................................. 2

- Paraglossae coniform ( flammeus -complex) ( Hypostenus).......................................................................28

2 Third abdominal tergite without paratergites ( Hypostenus)........................................................................3

- Third abdominal tergite with paratergites....................................................................................................5

3 Elytra unicolorous; front narrower (FW: HW = 0.42). Spermatheca as in Fig. 13 (in Puthz 2003). Male unknown. BL: 3.0– 4.2 mm. China: Hainan ........................................................... S. fellowesi Puthz, 2003

- Elytra bicolorous; front broader (FW: HW>0.44).................................................................................... 4

4 Forebody with interstices reticulately sculptured; pronotum and elytra slightly glossy with punctation very dense; abdominal punctation moderately coarse. Spermatheca as in Fig. 14 (in Puthz 2003). Male unknown. Bl: 3.0– 4.2 mm. China: Hainan ....................................................... S. hainanensis Puthz, 2003

- Forebody with interstices smooth; pronotum and elytra glossy with punctation less dense; abdominal punctation fine to very fine. Aedeagus as in Fig. 6 (in Puthz 1981). BL: 4.0–5.0 mm. Vietnam ............... .......................................................................................................................... S. echiniventris Puthz, 1981

5 Only 3rd abdominal tergite with complete paratergites. Elytra with or without spots ( Hypostenus) ........ 6

- Abdominal tergites 4–6 with narrow to very narrow linear margination ( Hemistenus). Elytra unicolorous, without elytral spots.................................................................................................................................. 25

6 Elytra unicolorous, without elytral spots.....................................................................................................7

- Elytra bicolorous, with elytral spots..........................................................................................................12

7 Elytral punctures distinctly delimited, moderately deep; punctation of frons coarse and moderately dense 8

- Elytral punctures indistinctly delimited, shallow; punctation of frons less coarse, sparse. Aedeagus as in Fig. 1, E (in Naomi 1988); spermatheca as in Fig. 1, F (in Naomi 1988). BL: 3.0– 3.8 mm. Japan: Amami- Oshima Is. ........................................................................................................ S. amamiensis Naomi, 1988

8 Male: aedeagus as in Fig. 1, D (in Naomi 1998), apical portion of median lobe triangular, longer than broad. BL: 3.0– 3.8 mm. Japan: Nansen Isls.: Toku Is............................................ S. tokunis Naomi, 1998

- Male: aedeagus as in Fig. C (in Naomi 1988), apical portion of median lobe spade-like, broader than long. BL: 3.2–4.1 mm. Japan: Okinawa-Hontô Is. ........................................................ S. punctifer Naomi, 1988

9 Smaller species; elytra broader than long.................................................................................................10

- Larger species, elytra at least as long as wide. Aedeagus as in Fig. 12 (in Puthz 1998a), spermatheca as in Fig. 5 (in Puthz 1998a). BL: 3.2–4.2 mm. Vietnam .......................................... S. deliculus Ryvkin, 1992

10 Punctation of forebody moderately dense, interstices strongly glossy, punctures distinctly delimited. Aedeagus as in Fig. 26 (in Puthz 2003). BL: 2.5–3.5 mm. China: Jiangsu .......... S. falsus L. Benick, 1940

- Punctation of forebody very dense, interstices slightly or not glossy, punctures less distinctly delimited .. 11

11 Interstices of pronotal punctation distinctly reticulate. Aedeagus as in Fig. 22, spermatheca as in Fig. 24. BL: 2.3–2.8 mm. China: Zhejiang ......................................................................... S. shenshanjiai sp. nov.

- Interstices of pronotal punctation indistinctly reticulate. Aedeagus as in Fig. 10 (in Tang et al. 2005), spermatheca as in Fig. 11 (in Tang et al. 2005). BL: 2.3–3.2 mm. China: Shaanxi ............................................ .......................................................................................................................... S. nigritus Tang et al., 2005

12 Head distinctly wider than elytra...............................................................................................................13

- Head narrower than elytra or nearly as wide as elytra..............................................................................21

13 Frons with punctation sparse and different in size. Aedeagus as in Fig. 12 (in Puthz 2003). BL: 3.0–4.0 mm. China: Guangdong ..................................................................................... S. cactiventris Puthz, 2003

- Frons with punctation dense and almost same in size...............................................................................14

14 Punctation of pronotum and elytra very dense, crowded, that of the pronotum irregular. Species best identified by their sexual characters ................................................................................................................ 15

- Punctation of pronotum and elytra dense but not crowded.......................................................................19

15 Punctation of elytra very densely crowded. Male: apical emargination 8th abdominal sternite very broad and shallow (Fig. 7)...................................................................................................................................16

- Punctation of elytra less dense, less crowded. Male: apical emargination of 8th abdominal sternite narrower, rounded (Figs. 12, 14) (exceptions: S. cooterianus, S. ovalis)......................................................17

16 Elytral spot shorter, not extending towards shoulder. Aedeagus as in Fig. 9, spermatheca as in Fig. 11. BL: 3.7–5.0 mm. China: Zhejiang ...................................................................................... S. zhulilongi sp. nov

- Elytral spot longer, extending towards shoulder. Aedeagus as in Fig. 20 (in Puthz 2003), spermatheca as in Fig. 19 (in Puthz 2003). BL: 3.5–4.7 mm. China: Fujian............................. S. lacrimulus L. Benick, 1942

17 Elytral spot shorter than half elytron length. Punctation of pronotum homogenous, very coarse. Aedeagus as in Fig. 18. BL: 3.7–5.0 mm. China: Zhejiang ................................................. S. jiulongshanus sp. nov.

- Elytral spot longer than half elytron length .............................................................................................. 18

18 Body smaller, punctation of pronotum inhomogenous, with moderately coarse and very coarse punctures. Aedoeagus as in Fig. 18 (in Puthz 2003). BL: 3.6–4.3 mm. China: Fujian ........... S. wuyiensis Puthz, 2003

- Body larger, punctation of pronotum homogenous, very coarse. Aedeagus as in Fig. 14. BL: 3.8–5.0 mm.

China: Jiangxi, Zhejiang ................................................................................................ S. lijinweni sp. nov. 19 Punctation on elytral spot very sparse, some interstices larger than diameter of punctures. Aedeagus as in Fig. 9 (in Puthz 2003). BL: 3.2–4.2 mm. China: Fujian.................................... S. cooterianus Puthz, 2003

- Punctation on elytral spot dense, interstices slightly larger than half diameter of punctures....................20

20 Body larger: 3.8–4.5 mm (forebody: 1.9–2.1 mm). Elytral spot longer than half elytron, extending towards shoulder. Aedeagus as in Fig. 14 (in Tang et al. 2005), spermatheca as in Fig. 15 (in Tang et al. 2005). BL: 4.1–4.7 mm. China: Zhejiang ........................................................................... S. ovalis Tang et al., 2005

- Body smaller: 3.2–4.1 mm (forebody: 1.6–1.7 mm). Elytral spot shorter than half elytron length, not extending towards shoulder. Aedeagus as in Fig. 6 (in Tang et al. 2005), spermatheca as in Fig. 7 (in Tang et al. 2005). BL: 3.6–4.3 mm. China: Hubei ..................................................... S. andoi Tang et al., 2005

21 Head scarcely wider than elytra; elytra broader than long; elytral spot indistinctly delimited. Aedeagus as in Fig. 1 (in Puthz, 1983). BL: 3.0– 3.5 mm. China: Guangxi .......................... S. splendidulus Puthz, 1983

- Head distinctly narrower than elytra; elytra longer than broad. Four very similar species with larger body...................................................................................................................................................................22

22 Elytral spot very large, extending towards shoulder (Fig. 1 in Hromádka 2001)......................................23

- Elytral spot smaller, not extending towards shoulder. Aedeagus as in Fig. 2 (in Puthz 1998b). BL: 3.8–4.8 mm. Vietnam .................................................................................................... S. aeneofulgens Puthz, 1998

23 Punctation of elytra very dense, crowded. Abdominal punctation denser, interstices on 7th tergite at most twice as wide as punctures. Aedeagus as in Fig. 2 (in Hromádka 2001), spermatheca as in Fig. 4 (in Hromádka 2001). BL: 3.7–4.7 mm. India: Uttar Pradesh ............................. S. panthera Hromádka, 2001

- Punctation of elytra less dense, not crowded. Abdominal punctation sparser, interstices on 7th tergite three times as wide as punctures........................................................................................................................24

24 Male: aedeagus as in Fig. 3 (in Puthz 1998b). BL: 3.5–4.7 mm. China: Guangxi, Zhejiang........................ ................................................................................................................ S. guangxiensis Rougemont, 1984

- Male: aedeagus as in Fig. 4 (in Puthz 1998b). BL: 3.3–4,7 mm. China: Sichuan......................................... ........................................................................................................................... S. aeneonitens Puthz, 1998

25 Body smaller: 2.6–3.6 mm ........................................................................................................................26

- Body larger: longer than 3.4 mm ................................................................................................................... .... Seven Japanese species: S. cirriformis Naomi, 1988; S. domburi Hromádka, 1979; S. kanzeon Naomi, 2004; S. longisetosus Puthz, 1993; S. nachiensis Puthz, 2001; S. nyorin Naomi, 2004; S. sakaii Naomi & Puthz, 1996; S. sawadaianus Hromádka, 1979; S. sugiei Naomi, 1997 .

26 Elytra strongly glossy with punctation irregular, slightly confluent, interstices smooth. Aedeagus as in Fig. 16 (in Puthz 2003), spermatheca as in Fig. 15 (in Puthz 2003). BL: 2.6–3.4 mm. China: Jiangxi ....... ................................................................................................................ S. huangganmontium Puthz, 2003

- Elytra slightly glossy with punctation regular and deep, scarcely confluent.............................................27

27 Frons nearly dull with punctation very dense. Aedeagus as in Fig. 37, spermatheca as in Fig. 39. BL: 2.6– 3.6 mm. China: Zhejiang .................................................................................... S. cirrus L. Benick, 1940

- Frons glossy with punctation sparse. Aedeagus as in Fig. 1, D (in Naomi 1988), spermatheca as in Fig. 1, E (in Naomi 1988). BL: 2.6–3.2 mm. Japan .............................................. S. yashiro Naomi & Puthz, 1994

28 Body broader and larger. Punctation of 6th and 7th abdominal tergites denser, interstices at most as large as punctures. Aedeagus as in Fig. 27, spermatheca as in Fig. 29. BL: 3.7–5.7 mm. China: Sichuan ........... ...................................................................................................................................... S. flammeus sp. nov.

- Body narrower and slightly smaller. Punctation of 6th and 7th abdominal tergites less dense, interstices up to twice as large as punctures. Aedeagus as in Fig. 32, spermatheca as in Fig. 34.BL: 4.0– 4.5 mm. China: Sichuan ....................................................................................................................... S. bostrychus sp. nov.