Characteristics: Brown-black with extensive yellow and some red checkering on dorsal wing. Forewing length: 25-28 mm.

Similar Species: Euphydryas editha quino (=wrighti) is similar but has more extensive red markings and less black than chalcedona. Chlosyne leanira wrightii is also similar in appearance to the Chalcedon Checkerspot.

Habitats, Behavior: Adults are readily attracted to moisture and also to flowers of Eriodictyon crassifolium (Yerba Santa) in many areas of southern California, e. g., the vicinity of Frazier Park (Kern County).

Distribution: The Chalcedon Checkerspot inhabits suitable areas from the coastal foothills to canyons in the Santa Ana Mountains and down to Irvine Park. The species appears to occur more frequently in the coastal foothills, especially in the hills near Laguna Canyon. Although the larval foodplant Mimulus grows in the hills north of Villa Park Dam, E. chalcedona has never been captured in this inland region. The Chalcedon Checkerspot may occur in the Brea Canyon region although all our butterfly records from that area are quite sparse (from inadequate collecting).

Flight Period: Our records indicate one brood flying from the middle of March into June. The peak emergence seems to extend from late March to early May.

Larval Foodplants: Large numbers of larvae are found both on Figwort (Scrophularia californica) and on Monkey Flower (Mimulus aurantiacus)  in Silverado Canyon behind the fire station almost every year. Ron Vanderhoff has also found and reared larvae here on Penstemon antirrhinoides and P. cordifolia. Erich Walter also has taken numerous larvae on Mimulus. Emmel and Emmel (1973) also report Penstemon antirrhinoides as the larval foodplant in the chaparral regions of Orange County, western San Diego County and western Riverside County. This plant grows abundantly in recently burned areas in the foothills and mountains of Orange County. Figwort (Scrophularia californica) is said to be of frequent occurrence in the chaparral and riparian woodland associations of Orange County (Boughey, 1968). Other foodplants recorded for California populations which might be utilized infrequently by Orange County populations include "Chinese houses" (Collinsia spp.-two species are of occasional occurrence in Orange County riparian woodland); Plantago spp., Castilleja spp. (Indian paintbrush), and wild honeysuckle (Lonicera -- two species in Orange County). Plantago is in the plant family Plantaginaceae. The other larval foodplants are members of the Figwort Family, Scrophulariaceae.

Other Remarks: Judging from the records and talks with older collectors, chalcedona has perhaps become less common in Orange County in the last forty years. The reasons for this are not clear, since suitable habitat has not been eliminated. Theodore Hower remarks that some populations in Orange County are more extensively marked with red than normal.

From Orsak, L. J. (1977). The Butterflies of Orange County, California. Center for Pathobiology Miscellaneous Publication #3. University of California Press, New York. 349pp.

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