Thressa longimaculata, Liu, Xiao-Yan, Yang, Ding & Nartshuk, Emilia P., 2011

Liu, Xiao-Yan, Yang, Ding & Nartshuk, Emilia P., 2011, Species of the genus Thressa Walker, 1860 from China (Diptera, Chloropidae), ZooKeys 129, pp. 29-48 : 36-38

Thressa longimaculata sp. n. Figs 2936

Diagnosis.

Thoracic pleuron brown except for katepisternum and katepimeron with black lower portion; paratergite and posterodorsal portion of anepisternum with a triangular yellow spot. Wing hyaline with a long brown spot near wing apex, costal cell and marginal cell somewhat tinged with brown. Cercus semicircular in dorsal view. Postgonite with basal 1/3 obviously narrowed.

Description.

Male. Body length 2.6 mm, wing length 2.0 mm

Head (Fig. 29) black without microtomentum, about 0.85 times as long as high, wider than thorax; face sometimes concave in lateral view, bright brown with a yellow medial stripe more or less on dorsal 1/2; epistoma yellow; frons black, about as long as wide, projecting only slightly in front of eye, almost entirely occupied by broad ocellar triangle; gena narrow, about 1/10 times as high as postpedicel; vibrissal angle obtuse; parafacial black, linear; postgena black; clypeus light black. Ocellar triangle very large and broad, smooth, black, shiny metallic blue, reaching to anterior margin of frons with broad apex; ocellar tubercle black. Occiput black. Cephalic setae and setulae black, weakly developed; if extremely short, in 1 row on the surface of the triangle; orb very minute, upright; oc extremely small; pvt small hair-like, upright, convergent; vte short than pvt and vti indistinct. Antenna darkish brown with thick grayish microtomentum, but pedicel with yellow ventral surface, postpedicel yel low at basoventral portion; postpedicel 2 times as long as wide, parallel-sided; arista pectinate, with 5 branches dorsally and 4 ventrally, apically with some short setulae, black except for basal segment yellow. Proboscis yellow with yellowish setulae and palpus black with black setulae.

Thorax (Figs 30, 31) shiny black without microtomentum, with granulated microsculpture, evenly covered with short setulae. Scutum strongly convex, almost as long as wide. Thoracic pleuron brown except for katepisternum and katepimeron with black lower portion; paratergite and posterodorsal portion of anepisternum with a triangular yellow spot. Scutellum about 0.5 times as long as wide; ap sc short, distinctly shorter than scutellum. Setae and setulae on thorax black. Legs yellow except for basal portion of mid coxae, tarsomere 5 brown. Setulae on legs yellow, but apical portion of tarsi with some brown setulae. Tibial organ distinct, oblong. Wing (Fig. 32) about 3.1 times as long as wide, hyaline with a brown spot near wing apex, costal cell and marginal cell somewhat tinged with brown; veins brown. Relative lengths of 2nd: 3rd: 4th costal sections = 5: 2.5: 1; discal cell narrow and long; crossveins r-m and m-m not approximate, r-m at basal 1/3 of discal cell. Halter pale yellow on knob, brown on stem.

Abdomen shiny blackish brown except tergite 5 yellow with a M-shaped black spot; venter yellow. Setulae on abdomen brown. Male genitalia (Figs 33-36): Epandrium short tubular, weakly sclerotized, yellow with long yellow setulae; surstylus basally broad with short spinous setulae, distally narrowed, attaching to epandrium anteroventrally. Cercus semicircular in dorsal view. Gonites arranged in a row; postgonite gradually narrowed distad and slightly convergent, basal 1/3 obviously narrowed, with sensory setulae; pregonite shorter than postgonite, basally broad and round, distally narrowed; basiphallus longer than wide, cylindrical; distiphallus cylindrical, longer than basiphallus, beyond lower margin of hypandrium, largely membranous but wea kly sclerotized on apical end; phallapodeme long, extended near base of basiphallus, with basal stalk broad in lateral view. Hypandrium narrow.

Female. Unknown.

Type material.

Holotype ♂, Fujian: Wuyishan (26°54'N, 116°42'E, 850m), 17. VII. 2010, Xiaoyan Liu. Male type specimen was stored in 75% ethanol.

Distribution.

China: Fujian.

Remarks.

The new species is somewhat similar to Thressa signifera Walker in the wing with a brown spot near the wing apex, costal cell and marginal cell somewhat tinged with brown. But it can be separated from the latter by the katepisternum and katepimeron with the black lower portion; the paratergite and posterodorsal portion of the anepisternum with one triangular yellow spot; the femora entirely yellow. In Thressa signifera , the thoracic pleuron has a white band; the femora are black except yellow distally ( Walker 1860, Nartshuk 1993).

Etymology.

The specific name is from the Latin longi- ( “long”) and maculatus ( “maculate”), refers to the long brown spot near the wing tip.