The double recessive "scarlet brown" gives a pure white eye color in Drosophila melanogaster, suggesting that the gene scarlet is a complete inactiva-tion of a gene which is solely responsible for an essential link in the process leading to brown eye, that the gene brown is similarly related to scarlet eye, and that red eye is the resultant of just these two processes. Bridges and Morgan have shown that scarlet, vermilion, and "scarlet vermilion" are indistinguishable, suggesting that these genes are complete inactivations of two genes. one of which is solely responsible for one essential link, the other for another, in the same chain reaction. The deduction that "vermilion brown" should also give a pure white eye color was found on test to be correct.