A redescription and neotype designation for Parelaphostrongylus odocoilei (Nematoda: Metastronglyoidea).

Parelaphostrongylus odocoilei is redescribed from worms collected from the type host (Odocoileus hemionus columbianus) in California, as well as material from experimentally infected mule deer (O. h. heminus) in Alberta. A single male specimen from the California material is designated as the neotype of P. odocoilei, the type species of Parelaphostrongylus. The male copulatory structures of the 3 species of Parelaphostrongylus (P. tenuis, P. anderscni, and P. odocoilei) are reviewed and a key for the identification of males is provided.