North American Butterflies and Moths List

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U.S. Geological Survey

Butterflies of North America

Butterflies of Wyoming

Pacuvius Duskywing (Erynnis pacuvius)
JPG -- species photo

Pacuvius Duskywing (Erynnis pacuvius [Lintner])

Wing span: 1 1/4 - 1 3/8 inches (3.2 - 3.5 cm).

Identification: Upperside brown to black; forewing with uneven dark bands and small submarginal spots. Hindwing fringes are white with brown scales at their bases in subspecies pacuvius (Utah, Colorado, Arizona, New Mexico) and brown in other subspecies. Male has a costal fold containing yellow scent scales; female has a patch of scent scales on the 7th abdominal segment.

Life history: To wait for females, males perch on hilltops all day, and sometimes patrol when there is a high density of males.

Flight: Two broods in southern California, Arizona, and New Mexico; one brood in the north.

Caterpillar hosts: Various wild lilacs including deer brier (Ceanothus fendleri), mountain whitethorn (Ceanothus cordulatus), hairy ceanothus (Ceanothus oliganthus), and others.

Adult food: Nectar from flowers including Ceanothus.

Habitat: Open coniferous forest, chaparral, cutover land.

Range: British Columbia south through the mountains of western North America to southern California, Arizona, New Mexico, Baja California Norte, and south to Veracruz, Mexico.

Conservation: Not usually required.

The Nature Conservancy Global Rank: G4 - Apparently secure globally, though it might be quite rare in parts of its range, especially at the periphery.

Management needs: None reported.


Scott, J. A. 1986. The butterflies of North America. Stanford 	University Press, 
     Stanford, Calif. 583 pages, 64 color plates.

Stanford, R. E. and P. A. Opler. 1993. Atlas of western USA butterflies including 
     adjacent parts of Canada and Mexico. Denver and Fort Collins, CO. 

Tilden, J. W. 1986. A field guide to western butterflies. Houghton-Mifflin Co., 
     Boston, Mass. 370 pages, 23 color plates.

Author: Jane M. Struttmann

State and Regional References:

Ferris, C.D. and F.M. Brown. 1980. Butterflies of the Rocky Mountain States. 
     University of Oklahoma Press. Norman.

Ferris, C.D. 1971. An Annotated Checklist of the Rhopalocera [Butterflies] of 
     Wyoming. University of Wyoming Agriculture Experiment Station Science 
     Monograph 23: 1-75.   

Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised 
     edition. Houghton Mifflin Co., Boston, Mass.

Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. 
     Privately published, Denver, Colo. 

Tilden, J.W. and A.C. Smith. 1986. A Field Guide to Western Butterflies. 
     Houghton Mifflin Co., Boston, Mass.
Pacuvius Duskywing (Erynnis pacuvius)
distribution map
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