Abstract
Adult resistance to DDT conferred by various regions of the second chromosome of a DDT-resistant strain of Drosophila melanogaster (Meigen) was analyzed using the quantitative genetic method of Thoday and a topical test procedure. Resistance was localized in a small region near and to the left of cn. Both the genetic method and the topical test technique were effective. Results are consistent with the idea that the number of loci responsible for insecticide resistance in D. melanogaster is not large.
