| abstract | The family Trachytidae and the genus Polyaspinus Berlese 1916 are redefined, and the type species of the genus, P. cylindricus Berlese 1916, is redescribed. Polyaspinus tasmanicus sp.nov. is described from Tasmania. The previously unknown male, deutonymph, protonymph and larva of P. higginsi Camin 1954 are described from North America. P. cylindricus is thelytokous while all the other species in the genus are bisexual. A key is provided for 6 of the 7 species, and the geographical distribution and relationsips of the genus are discussed. |