Barred eye—a new sex-linked character—appeared in Drosophila in a single red-eyed male fly and its dominance is constant over the normal eye. The broad bar of the heterozygous females distinguishes them from the homozygous ones with a narrow bar. The viability of the stock makes it valuable for linkage experiments. By taking the percentage of cross overs as an indication of distance on the chromosome, we can place the factor for barred approximately at 56.