In the upper Feather River drainage occur highly variable populations phenotypically intermediate between Phyciodes campestris campestris and the endemic high-Sierran P. c. montana. The population of this complex in Sierra Valley was formerly one of these, but it went extinct for unknown reasons. Today we find-rather uncommonly-a montana-type animal in the same area. The metropolis of the intergrading populations now seems to be the vicinity of Caribou Road, near Highway 70, where every conceivable intermediate phenotype can be taken. The former Sierra Valley population was at least partially double-brooded, and fed on Aster.