Key to species of the genus Brachynervus from South Korea

1. Clypeal apical margin round, without notch (Fig. 2A & 2B). Mesoscutum entirely black in dorsal view (Fig. 2D) ························································ B. beijingensis

- Clypeal apical margin with a median notch (Fig. 3B). Mesoscutum with yellow stripes or apots in dorsal view (Fig. 3D)····························································· 2

2. Mesoscutum with yellow spots on lateral lobs (Fig. 3D). Second discal cell irregularly pentagonal (Fig. 3H) ····························································· B. confusus

- Mesoscutum with four longitudinal yellow stripes and entirely apically. Second discal cell regularly pentagonal ································································ B. tsunekii