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 × 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 × as long as wide in A. silvanus), more elongate pronotum (1.3 × longer than wide vs. 1.1-1.2 × 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 × 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).