Hesperia uncas
Uncas Skipper

Sub-Family Description:
Alternate Common Names:White-Vein Skipper.

The caterpillar is light brown with a dark brown head that is marked with off-white.
Adult: This is a medium-sized skipper, with a wingspan of 1 to 1 5/8 inches. The upperside is brownish orange, darker along the edges, and marked with white, irregularly-shaped patches on the tip of the forewing. Males have a stigma (patch of scent scales used in attracting females) that forms a slanted blackish streak on the forewing. The underside of the forewing is marked as above but appears duller and may have more white.  The underside of the hindwing is greenish brown and marked extensively with white, both along the veins and in a curved row across the center of the wing.

This species ranges from central Alberta to southern Manitoba, south through the western halves of the Dakotas to northern Texas, and west to northern Arizona, Nevada, and in parts of Idaho, Montana, and Colorado. In Idaho, it occurs in the south central part of the state.

It occurs in prairies, sagebrush steppe, and open woodlands.

Caterpillars feed on the leaves of grasses including blue grama grass (Boutelous gracilis).

Adult: Butterflies drink flower nectar.

Caterpillars construct shelters from leaves tied with silk. There are two generations of caterpillars each year through most of its range, with possibly several in the south and only one at high elevations. Adults generally fly from late April through September through most of its range, and from mid-June through July at high elevations. Occasionally adults may stray into Iowa and Minnesota. The overwintering stage is unreported.

Males perch generally on small hilltops to wait for receptive females. Females lay light green eggs singly on or near host plants

Idaho Status: Unprotected nongame species.
Global Rank: G5
populations levels are secure, but may be of concern in the future.

Ferris, C. D. and F. M. Brown. (eds.) 1981. Butterflies of the Rocky Mountain States. Univ. of Oklahoma Press, Norman, Oklahoma, USA, 442 pp.

Opler, P. A., H. Pavulaan, and R. E. Stanford. 1995. Butterflies of North America. Jamestown, North Dakota, USA: Northern Prairie Wildlife Research Center Home Page. http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/bflyusa.htm (Version 05Nov98).

Opler, P. A. and A. B.Wright. 1999. A Field Guide to the Western Butterflies.   Second Edition.  Peterson Field Guide Series. Houghton Mifflin Company, New York, New York, USA, 540 pp.

Pyle, R. M. 1981. National Audubon Society Field Guide to North American Butterflies. Alfred A. Knopf, Inc., New York, New York, USA, 924 pp.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford, California, USA, 583 pp.

Stanford, R. E. and P. A. Opler. 1993. Atlas of Western U.S.A. Butterflies (Including Adjacent Parts of Canada and Mexico). Published by authors, Denver, Colorado, USA, 275 pp.