Diagnosis.

Head nearly as wide as or slightly narrower than base of mesonotum; inner area of pronotum generally concolorous to outer dilatation; male abdomen cylindrical, much longer than distance from head to cruciform elevation and slightly widest across 4th abdominal segment and wider than base of mesonotum; male tymbal cover very small and semicircular, mostly exposing tymbal in dorsal view; male 8th abdominal tergum mostly covered with white powder; ovipositor not protruding beyond abdominal segment 9; male operculum scale-like, roundish, and not extending beyond 2nd abdominal sternum; wings hyaline; 6th apical cell of forewing about as long as or longer than twice of 5th apical cell in median length. Based on Lee and Hayashi (2003).

Distribution.

China, Taiwan, Vietnam (Fig. 5).

Remarks.

This genus is similar to Leptosemia, Terpnosia and Euterpnosia (see Introduction).

Etymology.

The species name refers to morphological feature such as spinosa for the uncus spines

Material examined.

Holotype ♂: VIETNAM [VC.Ho.0650, Phu Ly, Ma Da-Vinh Cuu NR, Dong Nai Province, 4.viii.2008, light trap, 11°24'42.4"N, 107°06'19.5"E, 100–150m, leg Hoang Vu Tru] (IEBR).

Paratypes (3 ♂♂): 2 ♂♂: VIETNAM [ VC.Ho.0626, 0631, Phu Ly, Ma Da-Vinh Cuu NR, Dong Nai Province, 31.vii.2008, 100–150m, leg Hoang Vu Tru] (IEBR); 1 ♂: [VC.Ho.0765, Phu Ly, Ma Da-Vinh Cuu NR, Dong Nai Province, 2.viii.2008, light trap and netting, 100-150m, leg Ta Huy Thinh] (BMNH).

Description.

Head (Figs 2A, 2B, 7, 8): head pale yellowish-brown with following markings: broad median longitudinal band on frons and supra-antennal plate, dark brown; postclypeus dorsally with two oblique oval dark brown patches, in facial view upper half with transverse brown bands, lower half blackish brown; lower half of anteclypeus blackish brown, area between eye and antenna on gena, lorum and apex of rostrum, dark brown. Head including eyes as wide as mesonotum at base; rostrum reaching posterior coxae.

Thorax (Figs 2A, 2B): pale yellowish-green, longitudinal broad band on pronotum narrowed centrally, longitudinal broad band on mesonotum, spot between submedian and lateral sigillae, scutal depression, two spots on lateral margin of mesonotum, central area of cruciform elevation, second anepisternum, anepimeron and katepisternum, dark brown. Pronotal collar with a small dentate projection.

Wings (Fig. 2A): fore and hind wings hyaline, with veins brown or fuscous, and costal margin tawny; fore wings slightly tinged and spotted with infuscations on most veins.

Legs (2B): pale yellow with markings as follows: fore leg with femur, tibia, metatarsus and pretarsus blackish brown, primary spine of femur dark brown, secondary spine dark brown; mid leg with coxa and femur pale yellow, tibia pale brown, apex of femur black, apex and base of tibia black, metatarsus and pretarsus dark brown, mesotarsus pale yellow; hind leg, with femur pale yellow, apex of femur dark brown, tibia pale brown, base of tibia dark brown, tibial spur, tibial comb, and thumb of tibial comb dark brown.

Abdomen (Fig. 2B): pale greenish brown in dorsal view, with a longitudinal broad dark brown streak, tergites 3–7 with their lateral margins edged pale brown (Fig. 2A); pale brown in ventral view, anterior margin of sternites III - VI and sternites VII and VIII dark brown; epipleurites 3–6 lighter than sternites (Fig. 2B).

Operculum (Fig. 2B): pale yellow-green, short, transverse, and not reaching beyond anterior margin of sternite II.

Male genitalia (Figs 3A, B): Pygofer oblong in ventral view, lateral lobe of pygofer narrower than medial lobe, the latter triangular and prominent; dorsal beak acute and blackish brown; uncus brown, darker at apex of uncus lobes, the latter strongly divergent with two apical spines, medial spine shorter and acuter than lateral spine; Anal styles and anal tube dark brown. Aedeagus very slender.

Measurements in mm: (4 ♂♂): body length excluding wings: 27.1–29.0 (28.1); fore wing length: 31.0–32.6 (31.8); head width: 6.7–7.2 (7.0); pronotum width: 6.7–8.1 (7.4).

Biology.

This species was collected by sweeping during the daytime and by light trapping at night in virgin rainforest at an altitude between 100 to150 meters.

Distribution.

Vietnam (Dong Nai Province).

Remarks.

Semia spinosa is distinguishable from Semia watanabei and Semia klapperichi by the body size, which is shorter than 30mm (in male) in Semia spinosa and longer than 35mm (in male) in Semia watanabei and Semia klapperichi, and from Semia klapperichi it differs in the infuscations on the hind wings which lack spots along the ambient veins present in Semia klapperichi (see Figs 4A, C). The new species also differs in the structure of the uncus which has the lobes strongly divergent with acute apical spines (see Figs 6A–C).