Key to species of Radicidus gen. n.

1 Elytra with coarsely punctate striae laterally and in posterior half (Fig. 4 A). Fifth abdominal ventrite with a glabrous patch apically (Fig. 6 A). Size slightly larger on average (4.7–6.2 mm)................................................... 2

- Elytra without coarsely punctate striae (Fig. 4 B). Fifth abdominal ventrite pubescent throughout (Fig. 6 B). Size smaller, less than 5.0 mm............................................................................ R. granitum sp. n.

2 Glabrous region of fifth ventrite smaller, not exceeding half the width of the ventrite. Parameres each divided into two projections (Fig. 7 A)......................................................................... R. ayacucho sp. n.

- Glabrous region of the fifth ventrite larger, extending three-fourths the width of the ventrite. Parameres not divided into two projections (Fig. 7 B)................................................................. R. surinamenesis sp. n.