North American Butterflies and Moths List

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Butterflies of North America

Butterflies of California

Western Tailed-Blue (Everes amyntula)
JPG -- species photo

Western Tailed-Blue (Everes amyntula [Boisduval])

Wing span: 7/8 - 1 1/8 inches (2.2 - 2.9 cm).

Identification: Narrow tail on hindwing. Upperside of male blue, female brown with blue at wing base. Underside white with black spots indistinct or lacking; single small orange spot near tail.

Life history: Males patrol and perch during the day. Females lay eggs on flowers or young seedpods of host plant. Caterpillars eat young seeds inside the pod, where they overwinter and pupate.

Flight: March-July. Several broods in southern California, a partial second brood in the southern Rocky Mountains, and one brood elsewhere.

Caterpillar hosts: Legumes with inflated pods including false lupine (Thermopsis), milkvetch (Astragalus), crazyweed (Oxytropis), and vetches (Vicia and Lathyrus).

Adult food: Flower nectar.

Habitat: Open - usually native - areas with low shrubs including chaparral, meadows, and open woodland.

Range: Alaska south through western North America and all western mountains to northern Baja California, east across Canada's prairie provinces to northern Michigan, Ontario, and the Gaspé Peninsula.

Conservation: Not usually required.

The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.

Management needs: None reported.

References:

Opler, P. A. and G. O. Krizek. 1984. Butterflies east of the  Great Plains. Johns 
    Hopkins University Press, Baltimore. 294 pages, 54 color plates.

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:

Brown, J.W., Real, H.G., and D.K. Faulkner. 1992. Butterflies of Baja 
     California. Lepidoptera Research Foundation, Beverly Hills, Calif.

Comstock, J.A. 1927. Butterflies of California. Privately published, Los 
     Angeles, Calif. [Facsimile available from 	Entomological Reprint 
     Specialists, Los Angeles, Calif.]

Dameron, W. 1997. Searching for butterflies in southern California.
     Flutterby Press, Los Angeles, Calif.

Emmel, T.C. Editor. 1998. Systematics of western North American butterflies.
     Mariposa Press, Gainesville, Florida.

Emmel, T. C. and J. F. Emmel. 1973. The Butterflies of Southern California. 
     Natural History Museum of Los Angeles County Science Series No. 26.

Garth, J.S. and J.W. Tilden. 1986. California Butterflies.  California Natural
     History Guide 51. University of California Press, Berkeley and Los 
     Angeles.
     
Langston, R.L. 1981. The Rhopalocera of Santa Cruz Island, California. Journal
     of Research on the Lepidoptera 18: 24-35.     

Miller, Scott E. 1985. Butterflies of the Califorenia Channel Islands. Journal
     of the Research on the Lepidoptera 23: 282-296.     

Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised 
     edition. Houghton Mifflin Co., Boston, Mass.

Orsak, L.J. 1977. The Butterflies of Orange County, California. Museum of 
     Systematic Biology, University of california, Irvine.

Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. 
     Privately published, Denver, Colo.

Steiner, J. 1990. Bay Area Butterflies: The Distribution and Natural History 
     of San Francisco Region Rhopalocera. Hayward, Calif.: Hayward State 
     University, Masters Thesis.

Tilden, J.W. and A.C. Smith. 1986. A Field Guide to Western Butterflies. 
     Houghton Mifflin Co., Boston, Mass.

Tilden, J.W. 1965. Butterflies of the San Francisco Bay Region. California 
     Natural History Guide 12. University of California Press, Berkeley and 
     Los Angeles.
Western Tailed-Blue (Everes amyntula)
distribution map
map legend

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