Key to males of the Chinese species of the Grouvellinus acutus species group

1 Apex of hind tibia with a conspicuous broad appendage (Fig. 1a); apex of penis abruptly attenuate subapically (Figs 9–10)................................................................................................ G. acutus

- Apex of hind tibia without such appendage, apex of penis more or less gradually tapering toward apex.................. 2

2 Ventral sac of penis well developed, ejaculatory duct with denticulations (Fig.12)........................ G. denticulatus

- Ventral sac of penis weakly developed, ejaculatory duct without denticulations (Fig. 15)................... G. fujianensis