Female:
- Head: Wider than long, with a width 1.2 times greater than its length. The vertex possesses numerous small, irregular punctures. The posterior ocelli are positioned a distance from the compound eye margin equal to the ocellus’s diameter.
- Compound Eyes: Oval-shaped, with a length 1.2 times greater than the width, nearly smooth or sparsely covered with short hairs.
- Frons: Features a protruding knob. The frons is not concave and has numerous sparse punctures.
- Antennae: 12-segmented, with an 8-segmented club. The scape is 5.3 times longer than wide and 4.5 times longer than the second antennal segment. The third antennal segment is approximately 2.5 times longer than the second segment. The fourth antennal segment is swollen, with a length and width that are nearly equal.
- Thorax: Longer than wide. The mesoscutum lacks a median groove, exhibiting numerous, irregular punctures of varying sizes and sparse hairs.
- Wings: The forewings are 3 times longer than wide and 2.5 times longer than the width of the thorax. The postmarginal vein of the forewing is twice the length of the stigmal vein.
- Abdomen: 3 times longer than wide and longer than the thorax. The tergites of the abdomen are covered with longitudinal striations.
- Coloration: Body is a metallic blue-black. Antennae and legs are black. Wing veins are brown. The legs and body are covered with long, sparse hairs, with the hair length equal to half the length of the hind femur. The base of the scape bears a few long hairs, sometimes as long as the width of the scape.
Male:
- Resembles the female in color and shape. 12-segmented antennae, filiform (thread-like).
Measurements:
- Body length: 4.7 – 5.2 mm.
Distinguishing Characteristics:
- This new species is similar to S. sinense, but differs from it in having a mesoscutum lacking a median groove, and the abdomen being blue-black (versus reddish-purple tinged with blue in S. sinense).
Distribution:
- Vietnam: Thai Nguyen, Vinh Phuc, Gia Lai.
Type Material:
- Holotype: 1 female, Thai Nguyen (Phu Luong), 18/4/1986 (V. Triapitxun);
- Paratypes: 2 females, same location and date as holotype; 6 females and 5 males, same location, 16-23/4/1986 (A. Sarkov); 1 female, Vinh Phuc (Tam Dao) 10/4/1986 (A. Sarkov); 1 male, Gia Lai (An Khe, Buon Loi), 7/7/1980 (Le Xuan Hue).