2 3/8-3" (60-76 mm). Male milk-white with black checks, gray patches, and red spots on HW above and below varying in size according to geographical area. Female similar; often has large gray patches and transparent areas on outer FW and occasionally red spots near inner HW edge above and below; waxy white pouch (sphragis) at tip of female's abdomen. Antennae of both sexes black.
Female Eversmann's Parnassian has HW spots that extend into band. Phoebus Parnassian has red spots on both FW and HW, and checkered antennae; female Phoebus has gray or dark sphragis.
Caterpillar usually black with rows of yellow or reddish spots; overwinters in decayed leaf litter and pupates in thin silken cocoon in spring. Bleeding heart (Dicentra formosa) serves as primary host plant in Pacific Northwest; other species of Dicentra are eaten elsewhere.
Flight 1 brood; July-July in Washington, May-August in California.
Forest edges at sea level in Northwest; moist, cool mountains and shaded canyons and ridges in drier parts of range.
Coastal SE. Alaska, south in Cascade and Sierra Nevada mountains to N. California and Yosemite, and east to Idaho, Montana, Wyoming, and Utah.
The Clodius Parnassian is the only parnassian whose distribution is restricted to North America. It is sometimes found in the same mountains as the Phoebus Parnassian but Clodius usually flies at lower altitudes. Slow and deliberate, it often pauses to take nectar from hawkbit and other wild flowers. Once common in the Santa Cruz Mountains and the Snake River Canyon, the Clodius Parnassian is now no longer found in those areas - many conservationists blame logging and dam building, but others attribute the loss to drought.