Mountain Checkered-Skipper (Pyrgus xanthus W. H. Edwards)
Wing span: 3/4 - 1 inch (2 - 2.5 cm).
Identification: Upperside is dark grayish brown with 2 broken, irregular rows of white spots across both wings. Underside is similar to upperside, but duller. White hindwing fringe is streaked with black to the edge of the fringe. Male does not have a costal fold.
Life history: Males patrol but usually perch in gullies all day to watch for receptive females. Eggs are laid singly on leaves or flowers of the host plants. Caterpillars make a webbed shelter in which they rest and feed.
Flight: One brood from April-June.
Caterpillar hosts: Various Potentilla species in the rose family (Rosaceae).
Adult food: Flower nectar and dung.
Habitat: High mountain clearings from 8000 to 10,500 feet in elevation.
Range: Southern Colorado to central Arizona and southern New Mexico.
Conservation: Monitor populations and habitats and determine conservation needs.
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: Take management action if necessary.
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:
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.