Phyciodes mylitta
Mylitta Crescent

Family:Nymphalidae
Family Description:
Alternate Common Names:
Mylitta Crescentspot, Thistle Crescent.
Description:
Caterpillar:
The caterpillar is small, typically less than an inch long, and is reddish brown to black in color, marked lightly with white to yellowish tiny dots and several lengthwise stripes. The body has branching spines, black ones along the back and orangish ones on the sides.
Adult: This is a small to medium-sized butterfly, with a wingspan of 1 to 1 inches. It is orange on the upperside and bordered with black. The bases of the wings are marked with thin, black, wavy lines. The forewing has orange spots in the black at the tip; the hindwing has a row of small black dots, followed by a row of crescent-shaped orange spots in the black border. Underneath, the forewing is orange and marked with brown lines and patches of yellow and possibly white. The underside of the hindwing is yellowish, marked with wavy brown lines, a curved row of small black dots, and a curved row of whitish, possibly faint, crescent-shaped spots along the edge. One of the crescents is particularly bright.

Range:
This species ranges from southern British Columbia south to southern California, Arizona, and New Mexico, and continuing south into Mexico. It extends east as far as central Montana, northwestern Colorado, and in isolated sections of Wyoming. It occurs through most of Idaho.

Habitat:

It can be found in a wide variety of habitats, including meadows, fields, disturbed areas, open woodlands, marshes, mountains, and canyons.

Diet:

Caterpillar: Caterpillars feed on the leaves of native and alien thistles, including species of Cirsium, Silybum, and Carduus.
Adult: Butterflies drink flower nectar.

Ecology:

There are many generations of caterpillars each year through most of its range. Young caterpillars may live together in small silk webs. Caterpillars of the year’s last generation overwinter in a physiological state called diapause. Adults generally fly from April through October in most of its range. Butterflies tend to remain in the same general vicinity, near a particular group of flowers, for example, for several days in a row.

Reproduction:

Males perch or actively patrol in search of receptive females. Females lay groups of off-white eggs on the undersides of thistle leaves.

Conservation:
Idaho Status: Unprotected nongame species.
Global Rank:

G5; populations are widespread, abundant, and secure.


References:
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.