Erynnis pacuvius
Pacuvius Duskywing

Sub-Family Description:

Caterpillar: The caterpillar is light green, dotted with white, and has short hair. The head is black and marked with red, orange, or yellow.
Adult: This skipper is medium-sized to fairly large, with a wingspan of 1 1/4 to 1 3/8 inches. It is dark brown to black on the upperside. The forewing is marked with irregular brown, gray and black spots or bands, and a row of hazy white dots along the outside edge. The hindwing varies in color, from brown to gray to black, has little to no markings, and has a light brown or white fringe. Males have a small fold, called a costal fold, on the front inside edge of the forewing, which covers yellow scent scales.   They lack the hindleg "hair" (tibial tuft) found on other duskywings.

This species displays a patchy range, from southern British Columbia south through California, and in parts of the southwestern U.S. down to Mexico. It occurs in Idaho mainly in the north.

Its preferred habitats include open woodlands, chaparral, and mountain meadows.

Caterpillars feed on various species of buck brush (Ceanothus spp.).

Adult: Butterflies drink flower nectar, often from buck brush (Ceanothus spp.).

There is typically one generation of caterpillars each growing season in the north and two in the south. Caterpillars overwinter in a physiological state called diapause. Adults generally fly from May through July.

Males perch to wait for receptive females, or may actively patrol for them if competition is heavy. Females lay green eggs on host plants. The eggs turn pink before hatching.

Idaho Status: Unprotected nongame species.
Global Rank: G5
populations levels are secure, but may be of concern in the future.

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.