A dark mutant ofSchistocerca gregaria, which appeared in a laboratory colony, is described. In this mutant, the coloration of the nymphs is similar to that of the normal phenotype and only the adults become dark a few days after fledging. The mutant is named, therefore, as "dark-adult". Crossing experiments demonstrated that this mutation is controlled by a single recessive Mendelian unit. This "dark-adult" mutant seems to be different from a conspecific"melanic" mutant described in the literature: in the latter, the coloration of both the nymphs and the adults is dark.