North American Butterflies and Moths List

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The Registry of Nature Habitats

U.S. Geological Survey

Butterflies of North America

Hops Azure (Celastrina humulus)
JPG -- species photo

Hops Azure (Celastrina humulus Scott and D. Wright)

Wing span: 13/16 - 1 1/16 inches (2.1 - 2.9 cm).

Identification: Upperside of male powdery blue. Female with extensive black and iridescent blue variably invaded by white scaling. Underside of hindwing mostly white with few black spots or none.

Life history: Caterpillars eat flowers.

Flight: One flight from mid-June to early July just after flight of Spring Azure .

Caterpillar hosts: Hopes (Humulus japonica) and lupine in one drainage.

Adult food: Flower nectar.

Habitat: Mountain foothill canyons and ravines from about 5800-6500', usually associated with patches of hops.

Range: Colorado Front Range from Larimer County south to El Paso County.

Conservation: Habitat may be threatened by the spread of alien weeds and resultant wildfires.

The Nature Conservancy Global Rank: G3 - very rare or local throughout its range or found locally in a restricted range

Management needs: Survey habitats and protect them from alteration and exotic plants.


Opler, P.A. 1999. A field guide to western butterflies.  Houghton-Mifflin Co., 
     Boston, Mass. 540 pages, 44 color plates.

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. 

Author: Jane M. Struttmann

Hops Azure (Celastrina humulus)
distribution map
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