Pachyonychis

Pachyonychis is a genus of flea beetles in the family Chrysomelidae containing a single described species, P. paradoxa, from the United States.

The name is extremely similar to a different flea beetle, Pachyonychus paradoxus, named in 1847, that occurs on the same host plant; Crotch, in 1873, erroneously thought that Clark's name was spelled the same as the other species, and replaced Clark's name.