North American Butterflies and Moths List

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Butterflies of North America

Butterflies of Wyoming

Pink-edged Sulphur (Colias interior)
JPG -- species photo

Pink-edged Sulphur (Colias interior [Scudder])

Wing span: 1 1/2 - 2 5/8 inches (3.9 - 6.6 cm).

Identification: Both sexes with conspicuous pink wing edges. Male yellow; female yellow or white (very rarely). Upperside of male with black border; border on female may be incomplete or only seen at tip of wing. Underside of hindwing clear yellow with single silver cell spot circled in pink.

Life history: Males patrol with a slow flight for females. Eggs are laid in midsummer on blueberry leaves, and young caterpillars overwinter. Most feeding occurs the following spring.

Flight: One flight from June-August.

Caterpillar hosts: Various blueberry plants (Vaccinium species) in the heath family (Ericaceae).

Adult food: Nectar from flowers of bristly sarsaparilla and orange hawkweed.

Habitat: Shrubby openings in woods, bogs, or scrub areas where Ericaceae grows; often in burned or logged sites.

Range: From British Columbia and eastern Oregon east through the Great Lakes area to northern New England. Isolated population in central Appalachians of northeast Pennsylvania, western Maryland, eastern West Virginia, and northwest Virginia.

Conservation: Mountain populations of southern Appalachians should be monitored.

Management needs: Investigate habitat management needs,if any, in southern Appalachian habitats.

The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.


Opler, P. A. and G. O. Krizek. 1984. Butterflies east of the  Great Plains. 
     Johns Hopkins University Press, Baltimore. 294 pages, 54 color plates.

Opler, P. A. and V. Malikul. 1992. A field guide to eastern  butterflies. 
     Peterson field guide #4. Houghton-Mifflin Co.,  Boston. 396 pages, 
     48 color plates.

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

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.
Pink-edged Sulphur (Colias interior)
distribution map
map legend

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