North American Butterflies and Moths List

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U.S. Geological Survey

Butterflies of North America

Muir's Hairstreak (Callophrys [Mitoura] muiri)
JPG -- species photo

Muir's Hairstreak (Callophrys muiri [Hy. Edwards])

Wing span: 7/8 - 1 inch (2.2 - 2.5 cm).

Identification: Upperside of male is dark brown with dark orange patches on lower outer edges of wings; female is tawny with dark margins. Underside is dark purple-brown with an iridescent green sheen. Postmedian line is very irregular; dark toward the base of wing, white toward the outer margin. Blue-gray patch near hindwing margin contains 3-4 reddish spots; 3-4 small black spots are near this patch.

Life history: To seek females, males perch on host trees all day. Eggs are laid singly on tips of host plant leaves, which the caterpillars eat. Chrysalids hibernate.

Flight: One brood from April-May.

Caterpillar hosts: Cypress, especially Sargent cypress (Cupressus sargentii) and MacNab's cypress (Cupressus macnabiana).

Adult food: Nectar from flowers of wild lilac (Ceanothus) and other plants.

Habitat: Hilly, rocky areas.

Range: California's Coast Ranges from San Luis Obispo County north to Mendocino County; Guadeloupe Island, Mexico.

Conservation: This butterfly is of moderate concern.

The Nature Conservancy Rank: T3 - Very rare or local throughout its range or found locally in a restricted range (21 to 100 occurrences). (Threatened throughout its range).

Management needs: Conserve as many habitats as possible. Inventory and monitor populations.


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

Muir's Hairstreak (Callophrys [Mitoura] muiri)
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