Euwallacea semirudis

97. Euwallacea semirudis (Blandford) *

Xyleborus semirudis Blandford, 1896a: 210.

Euwallacea semirudis (Blandford): Wood, 1989: 173.

Thai distribution: S: Nakhon Sri Thammarat. New to Thailand.

New records: Nakhon Sri Thammarat, Chang Klang Distr., 08° 20' 59.7'' N, 99° 40' 14.6'' E, 70 m, durian plantation, EtOH trap, 01.xii.2009 (W. Sittichaya) (1); Khao Luang NP, headquarters, 08° 22' 21.6'' N, 99° 44' 14.7'' E, 196 m, EtOH trap, 1.iv.2010 (W. Sittichaya) (1).

Other distribution: ‘Borneo’, Indonesia (Java, Sumatera), Malaysia (E. & W.). The species also occurs in Brunei Darussalam (R. A. Beaver, unpublished records). (3)

Taxonomy: Wood (1989) synonymised this species with the Afrotropical species, Euwallacea xanthopus (Eichhoff). In view of the discovery of sibling species in the closely related species, Euwallacea fornicatus (see above), and the presence of small morphological differences, it seems advisable to keep the species separate at present. E.semirudis differs from E.xanthopus in the following characters (E.semirudis characters given first): mean length 2.95 mm, range 2.80–3.15 mm vs mean 2.65 mm, range 2.40–2.90 mm; elytral declivity somewhat flattened and matt vs evenly convex and shining; declivital striae 1 and 2 weakly impressed vs declivital striae 1 and 2 not impressed; declivital interstriae 1–3 usually lacking hairs except at the top of the declivity, and with granules irregularly spaced vs declivital interstriae each with a regularly spaced row of granules bearing hairs extending to apex.

Biology: Polyphagous (Browne 1961a). The gallery system resembles that of E.interjectus (see above) in larger stems. In smaller stems, the initial gallery is circumferential, and the brood develop in one or two longitudinal branches (Browne 1961a).

Illustrations: D (Nunberg 1959 as Xyleborus sereinuus Eggers).