Bengalia chiangmaiensis Kurahashi & Tumrasvin, 1979

(Figs 21–36)

Bengalia chiangmaiensi s Kurahashi & Tumrasvin, 1979: 298. HoloType ♂ (BPBM; noT examined), by original designaTion. Type locality: Thailand, N. W. Chiangmai Province, Chiangdao.

Bengalia chiangmaiensis: Kurahashi & Chowanadisai (2001: 202; Laos) (two males in BPBM; examined).

Bengalia chiangmaiensis: Verves (2005: 238; catalogue entry).

Bengalia chiangmaiensis: Kurahashi & Bunchu (2011: 263) (Thailand records; some listed below).

Diagnosis. Male. Length: 12.0–14.0mm (n=4). Frons at vertex / head width ratio 0.31–0.33 (mean 0.32, n=4). Anepimeron with almost exclusively black setulae, reaching katepisternum anteroventrally, but with some pale setulae in lower hind corner (Fig. 25). Most of T5 pale dorsally (Figs 35–36). Femora darkened in less than distal half (Fig. 35). ST5 flap transversely oval, but without projections beside it (Figs 28, 30; viewed under different angles). Terminalia very dark. Cerci with setose prongs diverging along more than distal half (Fig. 21). Surstylus with a ventral projection basally and a rounded tip (Fig. 23). Bacilliform sclerite process triangular, broad basally, with blunt tip (Fig. 22). Pregonite weakly sclerotized distally, tip bifurcate. Postgonite with an expanded distal portion and a pointed process shaped like a bird’s head with a beak (Fig. 24). Semidomes (sd) angulate in dorsolateral corner (Figs 31, 34). Distal lip process (dlp) shaped like a gutter, flat in the bottom, with low vertical lateral walls projecting dorsally (Figs 31–34). Distiphallus with a midventral keel basally (Fig. 32).

Female. Length 10.0mm (n=1). Frons at vertex / head width ratio 0.33 (mean 0.33, n=1). Anepimeron with black setulae in upper half and pale setulae in lower half, these being much more numerous than in the male.

Discussion. This is a rare species with a peculiar distal lip projection and semidomes, quite unlike other members of the Bengalia torosa species-group. The pre- and postgonites are also of exceptional shape.

Biology. Unknown.

Distribution. Laos *, Thailand *.

Material examined (non-type). BPBM. Laos: 1 ♂, labelled (1) LAOS: / Vientiane Prov. / Ban Van Eue / 15.V.1966 [printed]; (2) Native Collector / RONDON-BISHOP MUS. / COLLECTION [printed]; (3) Bengalia ♂ / chiangmaiensis / Ku. et Tum., 1979 / Det. H.Kurahashi [printed] [Already dissected when received; the terminalia were previously stored in a glass microvial with a cork stopper; the lacquered black pin was corroded and black substances had moved through the cork and into the glycerol fluid and apparently had stained all genital parts black; I moved terminalia to a new glass microvial with a soft white plastic stopper and changed the glycerol]; • 1 ♂, labelled (1) LAOS: / Vientiane Prov. / Ban Van Eue, 750 m / forest streambed / 10-11.IV.1965 [printed]; (2) 9 [number in pencil on circular orange label]; (3) J.L.Gressitt / Malaise Trap / BISHOP MUSEUM [printed]; (4) Bengalia ♂ / chiangmaiensis / Ku. et Tum., 1979 / Det. H.Kurahashi [printed] (Fig. 26) [Already dissected when received; the terminalia were previously stored in a glass microvial with a cork stopper; I moved the terminalia to a new glass microvial with a soft white plastic stopper and changed the glycerol; hypandrial sclerite brittle]. [None of the BPBM terminalia vials contained an ST5 flap.] NSMT. Thailand: 1 ♂, labelled (1) THAILAND: Chiang / Mai Prov., Doi / Sthep, 1000m / 9–15.V.1988 A6 / Col. H. Kurahashi; (2) Bengalia ♂ / chiangmaiensis / Ku. et Tum., 1979 / Det. H. Kurahashi [printed labels] (Fig. 29); • 1 ♂, 1 ♀, labelled (1) THAILAND: 1000m / Chiangmai Prov. / Doi Sthep / 16.VII.1989 / Col. H. Kurahashi; (2) Bengalia ♂ [or ♀] / chiangmaiensis / Ku. et Tum., 1979 / Det. H. Kurahashi [printed labels]. [Both NSMT males with intact ST5 flaps in situ.]