Harford's Sulphur (Colias harfordii Hy. Edwards)
Wing span: 1 3/4 - 2 inches (4.4 - 5.1 cm).
Identification: Upper surface of male a rich yellow, wing bases not darkened. Cell spot in front wing is medium-sized and black, often with a white center. Forewing border wide, hindwing border narrower. Cell spot in hindwing not noticeable. Female resembles male but border less well-defined, in some cases reduced or lacking.
Life history: Males patrol open areas to find receptive females. Eggs are laid singly on the underside of host plant leaves; caterpillars eat leaves. Larvae hibernate.
Flight: Two flights from February-May and from June-August.
Caterpillar hosts: Rattleweed (Astragalus douglasii) in the pea family (Fabaceae).
Adult food: Flower nectar from thistles and mints.
Habitat: Open chaparral and woodland clearings.
Range: Southern California coastal ranges and canyons from Kern County south to San Diego County.
Conservation: Not usually required.
Management needs: Not reported.
The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
Emmel, T. C. and J. F. Emmel. 1973. The butterflies of southern California. Science Series 26. Natural History Museum of Los Angeles County, Los Angeles, California. 148 pages, 10 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:
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.