Two male morphs occur in populations of Nala lividipes (Dufour), the black field earwig, and of Labidura truncata Kirby, the common brown earwig, distinguished by the presence or absence of a tooth at the mid-point on each forceps branch. Multivariate morphometric analyses using discriminant function analysis applied to measurements of various body parts of wild-caught specimens showed that the morphs were statistically separate in both species. In each species female size is intermediate to that of the 2 male morphs. The results are discussed on the basis of natural selection, and possible reasons given for the maintenance of 2 male morphs but only 1 female morph.