Key to species of the genus Chilocorus from China

1. Elytra without spots .......................................................................................................................... 2 – Elytra with spots ..............................................................................................................................11

2. Elytra entirely black or outer margin black ...................................................................................... 3 – Elytra entirely red (Fig. 1a) ......................................................................... C. politus Mulsant, 1850

3. Elytra entirely black .......................................................................................................................... 4 – Only outer margin of elytra black ..................................................................................................... 7

4. Body round ....................................................................................................................................... 5 – Body heart-shaped (Fig. 2a) ....................................................... C. yunlongensis Cao & Xiao, 1984

5. Dorsum without metallic lustre ........................................................................................................ 6 – Dorsum with bluish lustre (Fig. 3a) ........................................ C. nigricaeruleus Li & Wang sp. nov.

6. Pronotum mostly black except lateral parts yellow (Fig. 4c) ................. C. nigrita (Fabricius, 1798) – Pronotum black except anterior angles yellow (Fig. 5c) .................................. C. melas Weise, 1898

7. Ground colour of elytra red .............................................................................................................. 8 – Ground colour of elytra yellow ....................................................................................................... 10

8. Body roundish.................................................................................................................................... 9 – Body heart-shaped (Fig. 6a ............................................................................. C. rubidus Hope, 1831

9. Scutellum black (Fig. 7 a–c); abdominal postcoxal line not reaching posterior margin of abdominal ventrite 1 (Fig. 7d) ................................................................................ C. chinensis Miyatake, 1970

– Scutellum red (Fig. 8 a–c); abdominal postcoxal line reaching posterior margin of abdominal ventrite 1 (Fig. 8d) ........................................................................................ C. rufitarsis Motschulsky, 1853

10. Head black, pronotum and outer margin of elytra black with bluish lustre (Fig. 9 ac) .................................................................................................................... C. hauseri Weise, 1895

– Head and pronotum yellow, outer margin of elytra black without bluish lustre (Fig. 10 ac) ................................................................................................... C. circumdatus (Gyllenhal, 1808)

11. Elytra with a pair of spots ............................................................................................................... 12 – Elytra with two or three pairs of spots ............................................................................................ 17

12. Black areas of dorsum with bluish lustre ........................................................................................ 13 – Black areas of dorsum without any metallic lustre ......................................................................... 14

13. Penis guide as long as parameres (Fig. 11h) ....................................... C. chalybeatus Gorham, 1892 – Penis guide distinctly shorter than parameres (Fig. 12g) ............................. C. shirozui Sasaji, 1968

14. Elytral spots small, apex of penis blunt .......................................................................................... 15 – Elytral spots relatively larger, penis constricted to a pointed tip (Fig. 13a, e–f) ................................ ........................................................................................................... C. hupehanus Miyatake, 1970

15. Penis and tegmen moderately stout ................................................................................................ 16 – Penis and tegmen strongly stout, penis guide subtriangular, widest at base, gradually converging apically to blunted tip in ventral view (Fig. 14e, h) .................... C. strenotubus Li & Wang sp. nov.

16. Penis guide approximately ¾ length of parameres in lateral view, distinctly expanded at basal ¼ in ventral view (Fig. 15 g–h) ......................................................................... C. kuwanae Silvestri, 1909

– Penis guide approximately 4/5 length of parameres in lateral view, approximately parallel from base to basal ½ (Fig. 16 g–h) .................................................................................. C. esakii Kamiya, 1959

17. Ground colour of elytra black ......................................................................................................... 18 – Ground colour of elytra brown ....................................................................................................... 19

18. Body length: 3.40–3.70 mm, broadly oval, dorsum with bluish lustre (Fig. 17a) .................................................................................................... C. alishanus Sasaji, 1968 – Body length: 4.30–5.30 mm, heart-shaped, dorsum without any metallic lustre (Fig. 18a) .............. .................................................................................................................... C. bijugus Mulsant, 1853

19. Body length: 3.33–3.67 mm, elytra dark brown, with three pairs of roundish yellow spots, arranged in a row before centre, penis guide as long as parameres (Fig. 19a, g) .............................................. ....................................................................................................... C. bipustulatus (Linnaeus, 1758)

– Body length: 3.80–4.67 mm, elytra dark brown, with a pair of transverse yellow strips, situated before centre, about ¾ elytra width, penis guide slightly longer than parameres (Fig. 20a, g) ........................................................................................................... C. geminus Zaslavskij, 1962