Key to species of the genus Piesocorynus in Dominican and Mexican amber.
| 1. | Elytron with tubercles on third interval | 2 |
| - Elytron without tubercles on third interval | 4 | |
| 2. | Elytron with one tubercle at base of second and third intervals --- P. unibullus sp. nov. | |
| - Elytron with two or three tubercles on third interval | 3 | |
| 3. | Elytron with two tubercles on third interval: one at base and one in middle | P. bibullus sp. nov. |
| - Elytron with three tubercles: one at base of second and third intervals, one in middle and one before apex of third interval | P. tribullus sp. nov. | |
| 4. | Antennae long, extending beyond humeri | 5 |
| - Antennae short, not reaching, or reaching humeri | 6 | |
| 5. | Elytra short. Pronotum elongate with sides evenly rounded | P. brevitectus sp. nov. |
| - Elytra elongate. Pronotum short with sides angular in middle | P. hamus sp. nov. | |
| 6. | Pronotum elongate. Elytra 1.4 times as long as pronotum | P. elongatus sp. nov
|
| - Pronotum short. Elytra 1.6-2.0 times as long as pronotum | 7 | |
| 7. | Elytra approximately equal in length and width | P. parategus sp. nov. |
| - Elytra considerably longer than wide (1.3-1.4 times) | 8 | |
| 8. | Body size large (4.8 mm). Punctures in striae of elytra large. Pronotum slightly longer than wide. | P. villosus sp. nov. |
| - Body size smaller (2.5 mm). Punctures in striae of elytra fine. Pronotum transverse | P. parvocorpus sp. nov. |
