Western Cloudywing (Thorybes diversus Bell)
Wing span: 1 1/4 - 1 1/2 inches (3.2 - 3.8 cm).
Identification: Upperside is dull brown with small pale spots. Males lack a costal fold. Underside is dull brown with gray scaling at margins; hindwing with indistinct dark bands.
Life history: To await females, males perch in small forest openings. Eggs are laid singly on the host plant.
Flight: One brood from June-July.
Caterpillar hosts: Cow clover (Trifolium wormskjoldii) in the pea family (Fabaceae).
Adult food: Flower nectar.
Habitat: Small openings in coniferous forests.
Range: Local and scarce. South Cascade mountains of Oregon and the Sierra Nevada of California.
Conservation: Seems to require open forest understory in yellow pine forests. Forest succession or replacement due to fire suppression may be a threat.
The Nature Conservancy Global Rank: G3 - Very rare or local throughout its range or found locally in a restricted range (21 to 100 occurrences). (Threatened throughout its range).
Management needs: None reported.
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:
Brown, F.M., Eff, J.D., and B. Rotger. 1957. Colorado Butterflies. Denver Museum of Natural History, Denver. Ferris, C.D. and F.M. Brown. 1980. Butterflies of the Rocky Mountain States. University of Oklahoma Press. Norman. Layberry, R.A., Hall, P.W. & Lafontaine, D.J., 1998. The Butterflies of Canada. University of Toronto Press, Toronto, ON. 280 pp. 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.