Key to male Triomicrus in eastern China.

1 Elytral subhumeral sulci absent........................................................................... 2

- Elytral subhumeral sulci present......................................................................... 5

2 Protibiae with apical protuberance (Fig. 8 E); Mesotibiae with apical denticle (Fig. 8 F); Antennomere XI lacking protuberance; apical lamina of abdominal sternite VII stout, widest near middle, posterior margin obliquely narrowed (Fig. 8 D). (Zhejiang).......................................................................... T. gutianensis Shen & Yin, sp. n.

- Protibiae and mesotibiae lacking protuberance or denticle...................................................... 3

3 Antennomere XI with large impression, as long as one-fourth of segmental length (Fig. 5 B–C); Apical lamina of abdominal sternite VII broadest near middle and arcuate toward apex (Fig. 5 D). (Zhejiang and Jiangxi)... T. contus Shen & Yin, sp. n.

- Antennomere XI with small impression at about one-sixth of segmental length................................... 4

4 Antennomere III wider than long, antennomere XI lacking impression near base (Fig. 3 A), Apical lamina of abdominal sternite VII stout, widest near middle, posterior margin obliquely narrowed (Fig. 3 D). (Anhui and Zhejiang)................................................................................................ T. anfractus Shen & Yin, sp. n.

- Antennomere III longer than wide (Fig. 2 A), antennomere XI with impression near base (Fig. 2 B–C); apical lamina of abdominal sternite VII slender, apex slightly curved laterally (Fig. 2 D). (Zhejiang)................ T. aculeus Shen & Yin, sp. n.

5 Elytral subhumeral sulci short, barely reaching half of elytral length............................................. 6

- Elytral subhumeral sulci long, reaching level of metacoxae................................................... 8

6 Protibiae with projection................................................................................ 7

- Protibiae lacking apical projection; apical lamina of abdominal sternite VII narrowed near base and pointed at apex (Fig. 7 D). (Zhejiang).................................................................. T. frondosus Shen & Yin, sp. n.

7 Protibiae with apical denticle (Fig. 10 D); antennomere XI with impression near middle (Fig. 10 B–C), apical lamina of abdominal sternite VII strongly transverse, pointed at apex of lateral margin (Fig. 10 E). (Jiangxi)..... T. hamus Shen & Yin, sp. n.

- Protibiae with distinct long apical projection (Fig. 14 D); apical lamina of abdominal sternite VII slender, narrowed at base and pointed at apex (Fig. 14 E). (Zhejiang and Fujian)........................... T. rougemonti Löbl, Kurbatov & Nomura

8 Head with median vertexal carina....................................................................... 9

- Head lacking median vertexal carina.................................................................... 10

9 Pronotum entirely covered with dense and coarse punctation (Fig. 1 A). (Zhejiang)....... T. abhorridus Shen & Yin, sp. n.

- Pronotum partially, finely and sparsely punctate (Fig. 6 A), apical lamina of abdominal sternite VII short, with rounded apex (Fig. 6 D). (Zhejiang)....................................................... T. damingensis Shen & Yin, sp. n.

10 Profemora distinctly enlarged......................................................................... 11

- Profemora normal; mesotibiae with triangular apical marginal projection (Fig. 13 E); antennomere XI with strongly prominent protuberance (Fig. 13 B–C); apical lamina of abdominal sternite VII transverse, strongly curved and pointed at apex (Fig. 13 D). (Zhejiang).................................................................... T. tibialis Shen & Yin, sp. n.

11 Protrochanters with long spine (Fig. 11 D); apical lamina of abdominal sternite VII (Fig. 11 E). (Anhui)............................................................................................. T. inaequalis Shen & Yin, sp. n.

- Protrochanters unmodified; antennomere XI with impression near middle (Fig. 12 B–C); apical lamina of abdominal sternite VII (Fig. 12 D). (Anhui)......................................................... .. T. mirus Shen & Yin, sp. n.