Key to species of the genus Oodescelis from China (based on males)

1. Anterior margin of pronotum deeply emarginate, anterior angles sharp........................................... 2

- Anterior margin of pronotum straight or nearly straight, anterior angles obtuse..................................... 6

2. Prosternal process, in lateral view, weakly obtuse apically; elytra elongate-oval, surface of elytral apex and epipleura dull, surface of epipleura without punctures or wrinkles (subgenus Planoodescelis)..................................... 3

- Prosternal process, in lateral view, sharp apically; elytra oval, surface of elytral apex and epipleura shiny, surface of epipleura with punctures and wrinkles (subgenus Acutoodescelis)....................................................... 4

3. Body black; pronotum widest at base, disc with dense punctures; elytra flattened, width at middle almost equal to that at base; abdomen without setal brush; metatibiae slightly curved; parameres much shorter than phallobase, base of parameres nearly as wide as apex, distal part wide and flat (Figs. 39–40).............. Oodescelis (Planoodescelis) kansouensis Kaszab, 1940

- Body brown; pronotum widest at middle, disc with very sparse punctures; elytra weak convex, width at middle obviously wider than that at base; abdominal ventrites 1, 2 and 5 with setal brush at middle; metatibiae straight; parameres nearly as long as phallobase, base of parameres strongly wider than apex, distal part narrow and long (Figs. 41–42)................................................................................ Oodescelis (Planoodescelis) lii Bai & Ren, sp. nov.

4. Pronotal punctures elongate, merging into distinct longitudinal long furrows at sides; metatibiae weakly curved................................................. Oodescelis (Acutoodescelis) punctatissima punctatissima (Fairmaire, 1886)

- Pronotal punctures round, part of them merging into extremely short longitudinal furrows at sides; metatibiae straight..... 5

5. Elytral punctures as large as those on pronotum but sparser; base of parameres not parallel laterally (Fig. 15)......................................................... Oodescelis (Acutoodescelis) punctatissima emmerichi Kaszab, 1940

- Elytral punctures smaller than those on pronotum but much sparser; base of parameres more parallel laterally (Fig. 17).......................................... Oodescelis (Acutoodescelis) punctatissima henanana Bai & Ren, subsp. nov.

6. Protibiae club-shaped (basal half thin, widening into club-shaped from middle to apex) (Figs. 5–6); parameres nearly as long as phallobase (subgenus Clavatoodescelis)................................................................. 7

- Protibiae evenly widening from base to apex (Figs. 7–8, 10); or protibiae axe-shaped (basal half thin, inner side strongly widening into axe-shaped from middle to apex) (Figs. 9, 11–14); parameres much shorter than phallobase.................... 8

7. Length of the tibial club on protibiae much longer than width in ventral view; apex of parameres strongly hook-liked curved to dorsal side in lateral view (Fig. 26)............................ Oodescelis (Clavatoodescelis) oblonga (Ballion, 1878)

- Length of the tibial club on protibiae nearly as long as width in ventral view; apex of parameres weakly hook-liked curved to dorsal side in lateral view (Fig. 24)....................... Oodescelis (Clavatoodescelis) acutanguloides Kaszab, 1940

8. Protibiae evenly widening from base to apex (Fig. 7); parameres not flattened, without longitudinal groove at middle, phallobase without lateral prominences or deep longitudinal groove (subgenus Convexoodescelis).................................................................... Oodescelis (Convexoodescelis) brevipennis brevipennis (Kaszab, 1938)

- Protibiae axe-shaped (Figs. 9, 11–14); or protibiae evenly widening from base to apex (Figs. 8, 10); parameres flattened, with longitudinal groove at middle, phallobase with lateral prominences and deep longitudinal groove (subgenus Ovaloodescelis) 9

9. Protibiae evenly widening from base to apex (Figs. 8, 10).................................................... 10

- Protibiae axe-shaped (Figs. 9, 11–14).................................................................... 11

10. Pronotum narrowly depressed along lateral margins from base to middle; inner side of metatibiae weakly curved at middle; outer margins of parameres with sharp hooks at apex in dorsal view (Fig. 29).................................................................................................. Oodescelis (Ovaloodescelis) ovalis (Ballion, 1878)

- Pronotum not depressed along lateral margins; inner side of metatibiae strongly curved at middle; outer margins of parameres with round hooks at apex in dorsal view (Fig. 27)................... Oodescelis (Ovaloodescelis) affinis (Seidlitz, 1893)

11. Length of the axe shorter than half length of protibiae (Fig. 14); outer margins of parameres with round hooks at apex in dorsal view (Fig. 37)............................................... Oodescelis (Ovaloodescelis) tibialis (Ballion, 1878)

- Length of the axe as long as half length of protibiae (Figs. 9, 11–13); outer margins of parameres with obtuse or sharp hooks at apex in dorsal view (Figs. 31, 33, 35).................................................................... 12

12. Outer margins of parameres with short and obtuse hooks at apex in dorsal view (Figs. 33, 35)........................ 13

- Outer margins of parameres with long and sharp hooks at apex in dorsal view (Fig. 31)............................. 14

13. Pronotum wider, not flattened laterally, depressed along lateral margins between base and middle; parameres long, narrowing forward from middle laterally (Fig. 33)..................... Oodescelis (Ovaloodescelis) similis similis (Kaszab, 1938)

- Pronotal disc more convex, weakly flattened laterally, not depressed along lateral margins; parameres short, narrowing forward from base laterally (Fig. 35)................................. Oodescelis (Ovaloodescelis) subattenuata Egorov, 1991

14. Parameres long, apex hook-liked curved to dorsal side in lateral view.. Oodescelis (Ovaloodescelis) heydeni (Seidlitz, 1893)

- Parameres short, apex not hook-liked curved to dorsal side in lateral view (Figs. 31–32).................................................................................... Oodescelis (Ovaloodescelis) pseudotibialis Skopin, 1973