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 Arixyleborus mediosectus (Eggers, 1923) Fig. 26G, H, L Xyleboricus mediosectus Eggers, 1923: 215. Arixyleborus mediosectus (Eggers): Schedl 1958c : 145. Arixyleborus angulatus Schedl, 1942a: 183. Synonymy: Wood 1989 : 170. Type material. Holotype (NMNH). New records. Laos: 10 km N Luang-Prabang, Mekhong river, 240 km N Vientiane, hills c. 250 m, poor settlem[ent], prim[ary] veget[ation], lux, iii.1993, Insomsay Somsy (MFNB, 1); Vientiane, Nan Van Eue, 15.xii.1966, native collector, ex light trap (BPBM, 1); as previous except: Gi Sion vill. De Tha Ngone, 28.ii.1965, J.L. Gressitt, ex light trap (BPBM, 1). Vietnam: Dong Nai, Cat Tien N.P., 11.42232 , 107.42834 , 128 m, 19.ii.2017, VN74, A.I. Cognato, T.A. Hoang, ex bottle trap (MSUC, 1). Diagnosis. 1.9-2.1 mm long (mean = 1.98 mm; n = 5); 2.86-3.33 x as long as wide. This species is distinguished by the protibiae posterior faces inflated, granulate; antennal club wider than long; pronotum lateral margin oblique; pronotum anterior margin without serrations; posterolateral carina acute, granulate. It can be further distinguished from the closely related A. silvanus by the more elongate form (2.6-2.7 x as long as wide in A. silvanus ), more elongate pronotum (1.3 x longer than wide vs. 1.1-1.2 x in A. silvanus ), the more finely granulate interstriae, and shallowly impressed striae at the apex of the elytral disc, and the presence of short coarse setae on the declivity rather than fine hair-like setae. It can be further distinguished from the closely related A. crassior by the more elongate form (2.5 x as long as wide in A. crassior ) and short coarse setae on the declivity. Similar species. Arixyleborus crassior , A. phiaoacensis , A. silvanus . Distribution. 'Borneo' , Cambodia, India (Andaman Is, Assam), Indonesia (Sumatra), Laos*, East & West Malaysia, Philippines, Sri Lanka, Thailand, Vietnam. Host plants. Polyphagous ( Maiti and Saha 2004 ). It has also been collected from the crop of an edible-nest swiftlet ( Collocalia fuciphaga ) ( Beaver and Browne 1979 ).