Key to the Chinese species of Passaloecus Shuckard

Female, Male: Female unknown in P. multituberculatus Ma & Li, P. petiolatus Ma & Li and P. tuberculiformis Bashir & Ma, sp. n.; male unknown in P. labrinigratus Ma & Li

1. Mandible tridentate apically............................................................................. 2

- Mandible bidentate apically............................................................................. 4

2. Palpi brown; clypeus with setae nearly 2 × midocellar diameters long; pronotal collar with conspicuous anterior carina; parapsidal line and scrobal sulcus inconspicuously impressed................................. P. corniger Shuckard

- Palpi yellow; clypeus with setae nearly 1 × midocellar diameter long; pronotal collar without anterior carina; parapsidal line distinct; scrobal sulcus deeply grooved.................................................................... 3

3. Labrum ivory to yellow; clypeus slightly convex; ocellar triangle with large, dense, conspicuous punctures; metasoma slightly constricted between segments I and II................................................. P. profundesulcatus sp. n.

- Labrum dark brown; clypeus flat; ocellar triangle with fine, dense punctures, slightly coriaceous; metasoma distinctly constricted between segments I and II............................................................ P. columnaris Ma & Li

4. Petiole slightly to distinctly longer than wide............................................................... 5

- Petiole not longer than wide............................................................................. 6

5. Metasoma distinctly constricted between segments I and II; admedian line inconspicuously impressed; lower gena with fine, dense punctures; ocellar triangle slightly convex; clypeus with midsize, dense punctures............ P. petiolatus Ma & Li

- Metasoma slightly constricted between segments I and II; admedian line distinct; lower gena with fine, sparse punctures; ocellar triangle moderately convex; clypeus with fine sparse punctures......................... P. tuberangustus sp. n.

6. Scrobal sulcus well defined, deep, with or without crenation................................................... 7

- Scrobal sulcus lacking................................................................................. 9

7. Omaulus present; ocellar triangle flat..................................................... P. turionum Dahlbom

- Omaulus absent; ocellar triangle slightly convex............................................................. 8

8. Hypersternaulus and episternal sulcus distinctly broadened; notaulus distinctly impressed; antero-lateral angle of pronotal collar moderately to markedly produced............................................... P. labrinigratus Ma & Li

- Hypersternaulus and episternal sulcus not broadened; notaulus shallowly grooved and crenulate; antero-lateral angle of pronotal collar lacking or slightly produced.......................................................... P. bisulcatus sp. n.

9. Parapsidal line and notaulus inconspicuously impressed...................................................... 10

- Parapsidal line distinct, crenulate; notaulus shallowly grooved and crenulate..................................... 14

10. Occipital carina narrow, distinctly crenulate; metanotum with sparse punctures.................... P. koreanus Tsuneki

- Occipital carina usual, simple; metanotum with dense punctures............................................... 11

11. Labrum not constricted subapically; gena ventrally with fine, sparse punctures; scutal patches present, oval; in female, ocellar triangle slightly convex, with large, dense punctures..................................... P. turanicus Gussakovskij

- Labrum distinctly constricted subapically; gena ventrally with midsize, dense punctures; scutal patches absent; in female, ocellar triangle nearly flat, with midsize, dense punctures.................................................... 12

12. Antero-lateral angle of pronotal collar markedly produced; propodeal enclosure reticulated medially; metasoma slightly constricted between segments I and II; in male, flagellum usual.............................. P. insignis (Vander Linden)

- Antero-lateral angle of pronotal collar slightly produced; propodeal enclosure irregularly rugose medially; metasoma not constricted between segments I and II; in male, flagellum slightly moniliform (constricted at regular intervals like a string of beads)............................................................................................. 13

13. Pronotal lobe ivory to yellowish........................................... P. monilicornis monilicornis Dahlbom

- Pronotal lobe black......................................................... P. monilicornis taiwanus Tsuneki

14. Gena with fine punctures: anterior margin of pronotal collar without carina.................... P. tuberculiformis sp. n.

- Gena with midsize to large punctures; anterior margin of pronotal collar with conspicuous carina..................... 15

15. Free margin of clypeus nearly truncate, slightly tridentate medially, teeth inconspicuous; frontal median carina lacking; pronotal collar without antero-lateral angle; lateral surface of propodeum shiny, nearly smooth anteriorly..... P. singularis Dahlbom

- Free margin of clypeus broadly produced medially, nearly rounded or arcuate apically; frontal median (frons medially) inconspicuously impressed; antero-lateral angle of pronotum markedly or moderately produced; lateral surface of propodeum with dense, fine, oblique longitudinal striation anteriorly..................................................... 16

16. Sternum I without keel; metasoma slightly constricted between segments I and II; occipital carina normal, simple; in male, flagellomeres II-X beneath with reddish brown tyloids; spinose tubercles present on the hind margin of metasomal tergum VI mesally, and mesopleuron shiny, with fine to midsize sparse punctures................... P. multituberculatus Ma & Li

- Sternum I with slender longitudinal keel medially; metasoma distinctly constricted between segments I and II; occipital carina narrowed throughout, distinctly crenulate; in male, flagellomeres III-VII beneath with brownish tyloids; spinose tubercles absent on hind the margin of metasomal tergum VI mesally, and mesopleuron coarsely coriaceous, with midsize to large dense punctures............................................................................. P. clypealis Faester