Brown body (bw) is a recessive, autosomal mutant in Anopheles quadrimaculatus (Say). Independent linkage was noted between stripe (st+) and bw, and an epistatic interaction was noted for the altered expression of st+ in bw homozygotes. Reciprocal autosomal translocations and a Y-autosome translocation were used to assign bw to the left arm of chromosome 2 and st+ to the right arm of chromosome 3.