This paper extends the usefulness of polyacrylamide gel electrophoresis to studies of mosquito taxonomy and mosquito vector ecology. Using a newly developed double staining technique, it is possible to unambiguously separate several species of Culex mosquitoes found in northern Indiana. These include Culex restuans, Culex pipiens pipiens, and Culex territans. Preliminary work indicates that Culex pipiens quinquefasciatus and Culex salinarius can also be identified by this method. This technique enables precise taxonomic identification of individual mosquitoes or pooled samples whether intact or damaged beyond identification by standard taxonomic methods. The small sample required (20 µl) per pool leaves sufficient material for virus isolation techniques.