1. Nine mutant characters, incomplete (ic), crumpled (cr), Interrupted (Ir), crooked (ck), ski (sk), balloon (ba), white (w), Plexate (Pt), and retracted (rt), are described. They were newly discovered in a species of Drosophila, the specific name of which, however, has not been determined yet. 2. Of these characters incomplete, crumpled, balloon, ski, and retracted appeared as autosomal recessives, while crooked and white as sex-linked ones. 3. Sex-linked gene Interrupted behaves as dominant though incomplete in its expression, the character being so variable that some heterozygous flies have interrupted or normal posterior crossveins. The homozygous flies seem to be sterile. 4. Plexate is a mutant character expressed by an autosomal dominant gene. The homozygous flies are not viable.