Undulivena thaiensis sp. n.

The new genus is quite different from the other genera of the tribe Erythroneurini in view of the forewing venation, patterns of patches and chaetotaxy of the subgenital plate. The CuA vein of forewing is waved, which is unique among known Erythroneurini.

Body yellow to beige with dark brown markings.

Head in dorsal view roundly produced, somewhat narrower than pronotum. Vertex usually with large median apical spot; coronal suture present or indistinct. Face with frontoclypeus and anteclypeus relatively slender. Pronotum broad, with posterior margin concave. Scutellum almost entirely dark, with obvious transverse impression. Forewing with claval vein distinct; MP vein slightly curved, confluent with R vein basally; CuA vein strongly sinuate. Hind wing with RA vein present.

Male abdominal apodemes small, not exceeding 3^rd sternite.

Male genitalia. Male pygofer lobe with posterior margin rounded, with one dorsal macrochaeta, several basolateral spine-like setae in distinct group and some similar scattered setae slightly more dorsally; dorsal appendage movably articulated basally, not extended beyond pygofer apex, connected with an extension of anal tube appendage articulated basally. Extension of anal tube appendage connected subbasally by ligament to sharp distal corners of aedeagal dorsal apodeme. Subgenital plate with few macrosetae laterally in basal half and numerous short stout setae on or near lateral and apical margin in lateral view. Style with 2^nd extension long, with few basal teeth on outer margin; preapical lobe distinct. Connective Y-shaped, with central lobe well developed. Aedeagal shaft very short, strongly laterally compressed, gonopore sub-apical on ventral surface; basal apodeme very short; preatrium well developed.

Thailand.

The new genus is very similar to Salka (from Oriental and Palearctic regions) in body shape and male genitalia, e.g., pygofer with dorsal appendages, long dorsal macrosetae and a group of basolateral macrosetae, and the presence of a median anterior lobe on the connective. It differs from Salka in having the venation of the forewing with CuA strongly sinuate, which is unique among known Typhlocybinae, and the subgenital plate with a few lateral macrosetae in basal half. The color pattern of the forewing is also very unusual with veins margined with yellowish white, contrasting with the dark wings.

The new generic name combines the Latin words undula and vena, referring to the undulate vein for the sinuate CuA vein of the forewing. The gender is feminine.

The forewing has yellow-whitish stripes along veins. The style apex expanded, with inner margin tooth-like medially, and the aedeagal shaft spindle-shaped in ventral view, with single small subbasal process.

Crown yellow, with large irregular central blackish brown patch (Figs 3, 7). Eyes grey (Figs 2, 6). Face pale beige marked with brown on postclypeus laterally and on anteclypeus basally (Figs 4, 8). Pronotum whitish yellow with large patch medially and hind margin, blackish brown (Fig. 1). Scutellum blackish brown (Fig. 1). Fore wing dark brown with veins margined with yellow-white (Fig. 1).

Male abdominal apodemes short, not extending to hind margin of 3^rd sternite (Fig. 12). Male genitalia as in generic description with male pygofer dorsal appendage tapered distally; extension of anal tube appendage hook-like apically (Figs 16, 23). Pygofer lobe with one dorsal macrosetae (Fig. 13). Subgenital plate with group of 4 macrosetae laterally in basal half (Figs 13, 14). Style with 2^nd extension of apical process expanded at midlength thereafter tapered to acute apex (Fig. 17). Aedeagal shaft with single small subbasal tooth-like process on left side, shaft spindle-shaped in ventral view with sharp basal corners and pair of converging lateral flanges distally, dorsal surface distally keel-like (Fig. 19); dorsal apodeme small tapered to apex in lateral view and with two sharp distal corners connected with ligament to ventral pygofer process; preatrium moderately long (Figs 19, 20).

Hind margin of female 7^th sternite convex medially (Fig. 9).

Measurements. Body length, males 3.2–3.3 mm, females 2.7–2.8 mm.

Figures 1–11. 

Undulivena thaiensis sp. n. (♂): 1 habitus, dorsal view 2 habitus, lateral view 3 head and thorax, dorsal view 4 face. (♀): 5 habitus, dorsal view 6 habitus, lateral view 7 head and thorax, dorsal view 8 face 9 abdomen of female 10 forewing 11 hind wing.

Holotype: ♂, THAILAND, Kanchanaburi, Khuean Srinagarindra NP, Chong Kraborg, 14°29.972'N, 98°53.035'E 210m, Malaise trap, 4–11.ix.2008, coll. Boonnam & Phumarin (QSBG). Paratypes: 3♂♂, 3♀♀, same data as holotype; 4♂♂, THAILAND, Kanchanaburi, Khuean Srinagarindra NP, Tha Thung-na/Chong Kraborg, 14°29.972'N, 98°53.035'E 210m, Malaise trap 6–13.xi.2008, coll. Boonnam & Phumarin (INHS, SKS).

This species can be distinguished by external and male genitalia characters (see generic Remarks).

The species is named for the type locality, Thailand. The name is adjectival.

Figures 12–23. 

Undulivena thaiensis sp. n. 12 abdominal apodemes 13 genital capsule 14 subgenital plate 15 subgenital plate, style and connective 16 pygofer dorsal appendage (upper part) and an extension of anal tube appendage (lower part), lateral view 17 style 18 connective 19 aedeagus, ventral view (broken line indicates ligament attaching to pygofer dorsal appendage) 20 aedeagus, ventro-lateral view 21 venation of forewing 22 venation of hind wing 23 anal tube appendage with an apex extension and pygofer dorsal appendage, dorsal view.