North American Butterflies and Moths List

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U.S. Geological Survey

Butterflies of North America

Butterflies of Northern Mexico

Cassius Blue (Leptotes cassius)
JPG -- species photo

Cassius Blue (Leptotes cassius [Cramer])

Wing span: 3/4 - 1 3/8 inches (2 - 3.5 cm).

Identification: Upperside of males pale blue; females with white patches. Underside tan with broken pale lines; forewing inner margin has "blank" areas with no spots.

Life history: Eggs are laid singly on flower buds of the host plant; caterpillars eat flowers and seedpods. Predation and parasitism may be discouraged by ants, which tend the caterpillars and feed on their sugary secretions.

Flight: All through the year in southern Florida and South Texas. Number of broods has not been determined.

Caterpillar hosts: Ornamental leadwort (Plumbago capensis), rattlebox (Crotalaria incana), hairy milk pea (Galactia volubilis), and lima bean (Phaseolus limensis).

Adult food: Nectar from shepherd's needle, lippia, and many other flowers.

Habitat: Subtropical thorn scrub, forest edges, weedy fields, residential areas.

Range: Florida and the Keys; Texas south through the West Indies, Mexico, and Central America to South America. Strays to New Mexico, Kansas, Missouri, and South Carolina.

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.


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.

Author: Jane M. Struttmann

State and Regional References:

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

Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. 
     Privately published, Denver, Colo.
Cassius Blue (Leptotes cassius)
distribution map
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