Horváth (1912b) divided the genus in four subgenera: Menodora, Norba, Omoplax, and Stephanitis s. str.; as indicated in the present catalogue, Omoplax was upgraded to genus by Takeya (1963). The remaining subdivision was generally followed by subsequent authors (Drake, Jing, and others), but not by Takeya (1963), who considered them as useful in identification keys, but irrelevant from a phylogenetic point of view, due to the existence of species with intermediate characters. We have decided here to keep the subgeneric division.