Cnestus improcerus (Sampson, 1921)

Smith, Sarah M., Beaver, Roger A. & Cognato, Anthony I., 2020, A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China, ZooKeys 983, pp. 1-442 : 1

Cnestus improcerus (Sampson, 1921) Fig. 33A, B, I

Xyleborus improcerus Sampson, 1921: 33.

Xylosandrus improcerus (Sampson): Beaver 1998: 183.

Cnestus improcerus (Sampson): Dole and Cognato 2010: 529.

Type material.

Holotype (NHMUK).

Diagnosis.

2.7-3.3 mm long (mean = 3.04 mm; n = 5); 1.67-1.74 × as long as wide. This species is distinguished by the presence of a mesonotal mycangial tuft on the pronotal base; elytral disc very short; procoxae widely separated; declivity bicolored, with the basal 1/2 black and the apical 1/2 with a pale translucent area; declivity flat; pronotum type 1 when viewed dorsally; antennal club type 2, with two sutures visible on posterior face; antennal funicle 4-segmented; protibiae distinctly triangular; declivital posterolateral margin moderately carinate from apex to declivital base along interstriae 7; declivital interstriae punctate, setose, and ground vestiture absent.

Similar species.

Cnestus ater , C. gravidus , C. mutilatus , C. testudo , Xylosandrus spp.

Distribution.

‘Borneo’, Brunei, East & West Malaysia, Thailand.

Host plants.

Recorded from Canarium ( Burseraceae ), Dipterocarpus ( Dipterocarpaceae ), and an unidentified genus of Lauraceae ( Browne 1961b).

Remarks.

Reported by Wood and Bright (1992) as occurring in India but no actual records have been found.

Figures

Figure 33. Dorsal, lateral and declivital view of Cnestus improcerus, 2.7 - 3.3 mm (A, B, I), C. mutilatus, 3.6 - 3.8 mm (C, D, J), C. nitidipennis, 2.8 - 3.2 mm (E, F, K), and C. protensus, 3.3 - 5.4 mm (G, H, L).