Synonyms and other taxonomic changes
originally placed in genus Papilio by Smith in 1797
specific epithet synonyms: ilavia, mirabelle, violae
Explanation of Names
Satyrium favonius (J. E. Smith, 1797)
3 subspecies in North America listed at All-Leps
: autolycus, favonius, ontario
Adult: upperside dark brown with dim orange spot near outer margin of forewing, and brighter orange spot near outer margin of hindwing between tails; underside light grayish-brown with jagged black and white line forming a W shape near margin of hindwing, distinctive tapering orange submarginal band, orange-capped black spot between tails, and large blue patch below tails at anal angle. As with many hairstreaks, antennae-like tails on hindwings are wiggled by gentle brushing together of the hindwings when the butterfly is at rest.
Larva: small, sluglike, yellowish-green with green dorsal stripes and yellow lateral stripe.
e US (TX-FL-MA-KS) - (MPG
Florida westward to eastern Texas and northward into Kansas, Missouri, Illinois, Ohio, Pennsylvania and Massachusetts. Also in southeastern Colorado and northeastern New Mexico. (1)
Distribution map at butterfliesandmoths.org
shows records from Maine in the northeast, and western Texas and New Mexico in the southwest.
The type specimen of subspecies S. f. ontario was collected in southern Ontario in 1868 but there have been no confirmed records of favonius in Canada since that time.
Woodland edges, oak scrub.
Larvae feed on young leaves of oak (Quercus spp.); hawthorn (Crataegus spp.) may also be a foodplant in the northeast.
Adults nectar on flowers such as New Jersey Tea (Ceanothus americanus), dogbane (Apocynum spp.), and White Sweet Clover (Melilotus alba).
One generation per year. Overwinters as an egg, laid on oak twig.
Regarding the common name, a PDF checklist
(2nd edition, 2001) by the North American Butterfly Association states:
"Prior to the First Edition, almost all authors treated Satyrium favonius and Satyrium ontario as separate species, using the English names, southern hairstreak and northern hairstreak, respectively. When these taxa were lumped in the First Edition, the Committee tried to develop an acceptable English name for the combined taxa, but was unable to do so. The Committee then decided to use the name Southern Hairstreak for the lumped taxa. This has created quite a bit of confusion and awkwardness, causing people to refer to the 'Northern' Southern Hairstreak and 'Southern' Southern Hairstreak. In an attempt to make this situation clear, the Committee has decided to change the English name of this species to Oak Hairstreak. Satyrium favonius favonius is now the 'Southern' Oak Hairstreak and S. f. ontario is now the 'Northern' Oak Hairstreak. Vote 3-1."
These names have not become popularized outside of NABA circles; most sources continue to call Satyrium favonius
the Southern Hairstreak. In fact, even Jeffrey Glassberg of NABA retains the name Southern Hairstreak in this list
of Mexican Butterflies published in September, 2005.
White M Hairstreak
) underside is similar but upperside is bright metallic blue with black borders - see nearctica.com