Etoblattina fossa was named by Scudder (1895). Its type specimen is Coll Huston 182, a tegmen (fragment), and it is an impression. Its type locality is Willis Creek near Steubenville, which is in a Stephanian terrestrial shale in the Conemaugh Formation of Ohio. It is the type species of Metaxys.

It was recombined as Metaxys fossa by Handlirsch (1906), Handlirsch (1906), Handlirsch (1920), Handlirsch (1922).