Boloria epithore
Pacific Fritillary

Family Description:
Alternate Common Name:
Western Meadow Fritillary.
Note: This species is referred to with the genus name Clossiana by some authors.
Caterpillar: Caterpillars are gray with darker sides streaked with black in the middle and marked with a reddish stripe near the bottom. The head is black, and the spines on both ends are black while those in the middle tend to be reddish.
Adult: The butterfly is medium-sized, with a wingspan of 1 3/8 to 1 3/4 inches. The upperside is bright orange, with black zigzagging lines on the interior half of the wings, followed by a row of blackish spots and a row of blackish dashes near the wings’ edge. Underneath, the forewing is pale brownish orange and marked similarly to the upperside. The underside of the hindwing is marked with wavy bands of brown, tan and yellowish beige near the base of the wing, while the outer half is grayish purplish brown and marked with a curved row of faint spots.

This is a butterfly of the Pacific Northwest primarily. It ranges from central British Columbia and southern Alberta south through Washington, Oregon, northern Idaho, and western Montana, and further south in California.

It tends to be in moist and open areas, such as meadows, marshes, mixed forests, and along streams.


Caterpillar: Caterpillars eat the leaves of various species of violets (Viola spp.).
Adult: Butterflies feed on flower nectar and are known to visit flowers of buck brush (Ceanothus velutinus) and members of the sunflower family (Asteraceae).

There is one generation of caterpillars each summer. Caterpillars overwinter in a physiological state called diapause during the winter, and emerge in spring to feed until they are ready to pupate. Adults generally fly from April to early August.

Males actively patrol for receptive females. The locations chosen by females to lay eggs have not been reported.

Idaho Status: Unprotected nongame species.
Global Rank:

G5; most populations are widespread, abundant, and secure. However, certain populations in the Santa Cruz mountains of California are dwindling.

Ferris, C. D. and F. M. Brown. (eds.) 1981. Butterflies of the Rocky Mountain States. Univ. of Oklahoma Press, Norman, Oklahoma, USA, 442 pp.

Opler, P. A., H. Pavulaan, and R. E. Stanford. 1995. Butterflies of North America. Jamestown, North Dakota, USA: Northern Prairie Wildlife Research Center Home Page. (Version 05Nov98).

Opler, P. A. and A. B.Wright. 1999. A Field Guide to the Western Butterflies.    Second Edition.  Peterson Field Guide Series. Houghton Mifflin Company, New York, New York, USA, 540 pp.

Pyle, R. M. 1981. National Audubon Society Field Guide to North American Butterflies. Alfred A. Knopf, Inc., New York, New York, USA, 924 pp.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford, California, USA, 583 pp.

Stanford, R. E. and P. A. Opler. 1993. Atlas of Western U.S.A. Butterflies (Including Adjacent Parts of Canada and Mexico). Published by authors, Denver, Colorado, USA, 275 pp.