North American Butterflies and Moths List

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The Registry of Nature Habitats
U.S. Geological Survey

Butterflies of North America

Butterflies of Alaska

Labrador Sulphur (Colias nastes)
JPG -- species photo

Labrador Sulphur (Colias nastes Boisduval)

Wing span: 1 1/4 - 1 3/4 inches (3.1 - 4.5 cm).

Identification: Upperside of both sexes dirty white or dirty green-yellow; black border contains white or greenish spots. Underside of hindwing has submarginal rows of black spots.

Life history: Overwinter as mature caterpillars.

Flight: One flight from late June-early August.

Caterpillar hosts: Plants of the pea family (Fabaceae) including milk vetch (Astragalus alpinus) and white clover (Trifolium repens).

Adult food: Flower nectar.

Habitat: Arctic and alpine tundra.

Range: Alaska south in Rocky Mountains to north-central Washington and northwest Montana.

Conservation: Not usually required.

Management needs: Not reported.

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 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:

Layberry, R.A., Hall, P.W. & Lafontaine, D.J., 1998.  The Butterflies of 
     Canada.  University of Toronto Press, Toronto, ON.  280 pp. 
Distribution Map Not Available

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