Caystrus dubius (Distant, 1921), comb. nov.

(Figs 125–129)

Agathocles dubius (unavailable): Distant (1921a): 4 (list).

Agathocles dubius Distant, 1921b: 42–43 (original description). Holotype: ♀, Laos, Luang Prabang, Van Nham (BMNH). Agathocles dubius: Hoffmann (1935): 89 (catalogue); Rider (1997): 402 (checklist).

Type locality. Laos, Luang Prabang Province, Van Nham .

Type material examined. Holotype: ♀, ‘Luang Prabang, / Van Nham. / 16. III.1918. / R. V.de Salvaza [p] / Indo China. / R. V.de Salvaza. / 1918‒1 [p] // Type / H. T. [p, round label with red frame marginally] // BRIT. MUS. / TYPE No. / HEM. [p] 916 [hw, pink label] // Agathocles / dubius / typus Dist. [hw] // Re-pinned / on stainless [p] // CAYSTRUS / DUBIUS (Dist.) [hw] / det. P. KMENT 2015 [p]’ (BMNH). The holotype is 14.63 mm long, pronotum width across humeral angles 6.71 mm. It is pinned, left metatarsus, right mesotarsus and both distiflagellomeres (IV) are missing.

Distribution. Laos (Distant 1921b).

Taxonomy. Examination of the holotype and its comparison with species of Agathocles and Caystrus revealed that it markedly differs from the first genus and fits well the second one, especially in having the body short, more regularly oval and relatively flat, head relatively short, mandibular plates not expanded forward and strongly narrowing anteriad, pronotum with sharp margins, and pale brown dorsal colouration with longitudinal yellowish unpunctured lines along corial veins (cf. Figs 125–126). Therefore, we transfer this species to the genus Caystrus, resulting in a new combination: Caystrus dubius (Distant, 1921), comb. nov. We did not find any important differences between C. dubius and C. obscurus, but we leave the decision on their synonymy for a furure revision of Caystrus .