Fig. 1

Map of the Pacific Coast of the United States, showing the 39° latitude southern boundary of the distribution of Cx. pipiens and the 36° latitude northern boundary of Cx. quinquefasciatus. The zone between the two latitudes (between 39° and 36°) is the hybrid zone for the two Culex species. Collections from this study are Cx. pipiens from Lewis and Clark Reservoir Washington, Cx. pipiens complex from Oroville California and Merced County California, and Cx. quinquefasciatus from Coachella California. Merced collections are further detailed in Table 1 and Fig. 2