Rhoenanthus (Potamanthindus) Lestage 1930

Key to species of subgenus Rhoenanthus (Potamanthindus): mature nymph

1. Spines on mandibular tusks base, lateral margins and dorsal surface (Fig. 10A, 10D)............................... 2

- Spines on mandibular tusks base only, other parts of tusks reddish to dark brown, smooth (Figs 2A, 10G)............... 4

2. Whole dorsal surface of mandibular tusks with numerous short spines (Fig. 10A)............................. R. sapa

- Apical half or more of tusks with limited number of larger spines............................................... 3

3. Spines on mandibular tusk progressively shorter, without subapical large spine (Fig. 10D)...................... R. youi

- Large subapical spine present, making mandibular tusk nearly forked.................................. R. coreanus

4. Apical brown part of mandibular tusk bent inward abruptly (Fig. 10G).................................. R. obscurus

- Apical brown part of mandibular tusk bent smoothly or near straight (Fig. 2A).................................... 5

5. Brown part of mandibular tusk near straight, relatively longer and slender (Fig. 2A)..................... R. hunanensis

- Brown part of mandibular tusk bent inward smoothly, relatively shorter and broader...................... R. magnificus