II. The vignai species group

Characters. Vertex without punctures; pronotal basal fovea composed of single long groove, outer groove absent; pronotum suborbicular or trapezoid, usually with two or three mid-lateral setae (rarely with one or four setae); outer surface of metatarsomere I glabrous or very faintly ridged at most on the basal half; in lateral view, the apical lamella of aedeagus more or less sinuate.

Geographical notes. This species group includes four known species. The distribution center of this group is more southern than the fischeri -group: three species were recorded from the area between southern Sichuan and northern Yunnan, while S. vignai was recorded from Sichuan, Shaanxi, Gansu and Ningxia (Fig. 1).