A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China Author Smith, Sarah M. Department of Entomology, Michigan State University, 288 Farm Lane, East Lansing, Michigan 48824, USA https://orcid.org/0000-0002-5173-3736 camptocerus@gmail.com Author Beaver, Roger A. 161 / 2 Mu 5, Soi Wat Pranon, T. Donkaew, A. Maerim, Chiangmai 50180, Thailand Author Cognato, Anthony I. Department of Entomology, Michigan State University, 288 Farm Lane, East Lansing, Michigan 48824, USA text ZooKeys 2020 983 1 442 http://dx.doi.org/10.3897/zookeys.983.52630 journal article http://dx.doi.org/10.3897/zookeys.983.52630 1313-2970-983-1 7DED4CE2934C4539945F758930C927F9 C890C7FD4B2D57A8B1A062305ED42D53 Planiculus Hulcr & Cognato, 2010 Planiculus Hulcr & Cognato, 2010a: 21. Type species. Xyleborus bicolor Blandford, 1894b; original designation. Diagnosis. Minute to small (1.7-2.4 mm), elongate (2.57-3.6 x as long as wide) and distinctly bicolored species. Planiculus is distinguished by the declivity flat, slightly broadened laterally; declivital interstriae 1 laterally broadened; lateral profile of declivity gradually descending; pronotum from dorsal view long, rounded anteriad (type 9), from lateral view elongated with low summit and elongate disc (type 8); antennal club approximately circular, obliquely truncate, type 2, segment 1 corneous, large, occupying at least basal 1/2 of club, segment 2 visible on posterior face; and protibiae distinctly triangular. In addition, the procoxae are contiguous, scutellum visible, flat, flush with elytra, the tuft on pronotal base associated with mesonotal mycangium is absent. Planiculus species are most easily confused with small Euwallacea and Xyleborus species but are distinguished by the declivity flat, slightly broadened laterally, with very few tubercles and smaller more elongate body, and rounded frontal margin of pronotum (type 7) that is never subquadrate (as in Euwallacea ). Similar genera. Euwallacea , Xyleborus . Distribution. Found throughout the Paleotropics and Australasia. Gallery system. The gallery system has a few branches more or less in one transverse plane with several small brood chambers extending longitudinally. Surface galleries between the phloem and sapwood may occur in thick-barked stems ( Browne 1961b ).