Key to the species of Clastopus

1 Circumocular depression shallow (Fig. 3). Elytral intervals convex; rows deep with small, barely visible punctures (Fig. 5) ... 2

- Circumocular depression deep (Fig. 2). Elytral intervals flat; rows shallow with large, clearly visible punctures (Fig. 4, 12).. 3

2 Margins of the intercoxal process of prosternum interrupted at the apex (Fig. 16). Elytral interrows smooth (Fig. 5).................................................................................................. C. ordinarius

- Margins of the intercoxal process of prosternum complete. Elytal intervals with delicate sculpturing.......... C. aberlenci

3 Body length: 11.0–12.0 mm. Pronotum broadest at the base. Male mesotibia without apical denticle. Male pro- and metafemora hairless.............................................................................. C. eurynotoides

- Body length: 7.0–10.0 mm. Pronotum broadest at at about 0.66 of its length. Male mesotibia with apical denticle. Male proand metafemora with row of hairs on the inner margin........................................................ 4

4 Body length: 7.0–8.0 mm. Intercoxal process of prosternum with ventral surface flat (Fig. 6). Male mesofemora with a denticle on inner side (Fig. 19)................................................................ C. griswoldi sp. nov.

- Body length: 8.8–10.0 mm. Intercoxal process of prosternum saddle-like (Fig. 7). Male mesofemora without a denticle................................................................................................ C. tenuiculus