Female: Head width is 2.5 times greater than its length. The vertex behind the posterior ocelli does not abruptly curve. The temporal region behind the compound eye is narrow, its width being less than half the width of the compound eye. The frons above the antennal sockets is not concave and lacks transverse striations. The head surface is almost without striations, and mostly smooth and shiny. The posterior ocelli are positioned far from the margin of the compound eyes; the distance between them is greater than the distance between the anterior ocellus and a posterior ocellus. The compound eyes are small, oval, longer than wide (11:7), and their length is greater than the length of the gena. The gena near the base of the mandible has striations forming a fan shape. The antennae are 12-segmented and clavate. The scape is 5 times longer than its width, 5 times longer than the radicle, and 3 times longer than antennal segment 2. Antennal segment 2 is longer than segment 3. Antennal segment 4 is equal in length to segment 3, longer than the subsequent 2 segments, and longer than its width. Antennal segments 5 and 6 have approximately equal length and width. The antennal club has 6 segments, and the combined length of these club segments is approximately equal to the length of the scape, and 4 times greater than their greatest width.
The thorax has approximately equal length and width. The mesoscutum lacks a mid-dorsal groove and has small, fine granular striations. The scutellum is rounded posteriorly, with striations similar to those on the mesoscutum in the middle, and is almost smooth and shiny on both sides and posteriorly. The forewing is about 3 times longer than wide, the postmarginal vein is reduced, and the marginal vein is 6 times longer than the stigmal vein.
The abdomen is 1.5 times longer than wide, and the same width as the thorax. Abdominal tergites 1 and 2 are almost equal in length, with longitudinal striations. Tergite 3 is the same length as tergites 1 and 2 combined. Subsequent tergites become progressively shorter and narrower. Tergites 3-6 are almost smooth and shiny.
The body is black. The antennae and legs are dark brown. The wing veins are brown, the wings are transparent, and the first abdominal tergite is dark brown.
The male resembles the female in shape and color. The antennae are 12-segmented and filiform. The scape is 5 times longer than its width and 5 times longer than the radicle. The subsequent antennal segments are normally developed.
Size:
Body length is approximately 1 mm. This species is closely related to T. chalcomelas Kozlov et Le, and they are distinguished from each other as described in the key.
Distribution:
Vietnam: Hanoi.
Type Material:
1 Female (holotype), Hanoi (Cau Giay, Nghia Do), 1/1980 (Le Xuan Hue); paratype: 1 Female, Hanoi (Cau Giay, Nghia Do), 30/3/1986 (V. Triapitxun) and 1 Male as above (A. Sarkov).