Trisinus cavernosus

Key to species of Trisinus cavernosus group (males)

1 Head ( Fig. 1A View FIGURE 1 ) appearing greatly transverse; lateral expansions of vertex ( Fig. 1B View FIGURE 1 ) extended laterally beyond eyes’ lateral margins; pronotum ( Fig. 1B View FIGURE 1 ) finely punctate on anterior half, with median longitudinal sulcus extending past middle for short distance; lateral margins greatly expanded; antennomeres 3–8 more slender, slightly elongate (S China: Guangdong)......................................................................................... T. tangliangi sp. nov.

– Head appearing moderately transverse; combined width of vertexal lateral expansions narrower than width across eyes; pronotum coarsely punctate on anterior half, with median longitudinal sulcus extending anteriorly well beyond middle; lateral margins moderately expanded; antennomeres 3–8 thicker, submoniliform........................................ 2

2 Cephalic cavity ( Ding et al. 2025: fig. 1A) generally V-shaped; vertex ( Ding et al. 2025: fig. 1C) lacking broad impression between projections and eyes (E China: Zhejiang, Jiangxi) ….......................... T. cavernosus Din, Niu & Yin

– Cephalic cavity ( Ding et al. 2025: fig. 2A) generally U-shaped; vertex ( Ding et al. 2025: fig. 2C) with broad impression between projections and eyes (E China: Zhejiang)............................... T. qingliangmontis Din, Niu & Yin