Lycaenid
Guides
Callophrys augustinus
Brown Elfin, Western Elfin (subspecies iroides)
Callophrys augustinus, the brown elfin, is a small lycaenid butterfly with a wingspan of 22–29 mm. Adults are active in a single generation from early May to early June. The species is univoltine with pupal hibernation. Larvae feed on Ericaceae species in eastern North America and a broader range of host plants in western populations.
Callophrys eryphon
Western Pine Elfin
Callophrys eryphon, the Western Pine Elfin, is a North American lycaenid butterfly with a transcontinental range spanning from British Columbia to Maine and south to southern California, Arizona, and New Mexico. Adults are sexually dimorphic: males are brown while females are orange-brown, both featuring bold patterned hindwings with dark bars and lighter chevron-shaped margins on the upper wing surfaces. The species is small, with body lengths of 19–32 mm and no tail on the hindwings.
Callophrys gryneus
juniper hairstreak, olive hairstreak
A small North American lycaenid butterfly with bright green undersides and highly variable wing patterns across its range. The species exhibits substantial geographic variation, with multiple named subspecies differing in coloration, pattern elements, and host plant associations. Males are territorial on host trees, and the species overwinters as a chrysalis. Taxonomic controversy persists regarding whether some subspecies merit full species status.
Callophrys hesseli
Hessel's Hairstreak
Hessel's Hairstreak is a small lycaenid butterfly endemic to Atlantic coastal wetlands of the eastern United States. The species exhibits complete ecological dependence on Atlantic white-cedar (Chamaecyparis thyoides), which serves as the exclusive larval host plant and provides adult camouflage habitat. Populations are patchily distributed and declining due to habitat loss, with state-level endangered status in Connecticut and G3 vulnerable ranking globally.
Callophrys niphon
Eastern Pine Elfin
Callophrys niphon, the eastern pine elfin, is a small butterfly in the family Lycaenidae native to North America. It is closely associated with pine habitats and has a single annual flight period that varies geographically. The species is distinguished from similar elfins by wing pattern characteristics.
Cotesia theclae
Cotesia theclae is a small parasitoid wasp in the family Braconidae that parasitizes caterpillars of lycaenid butterflies. The species was described by Riley in 1881 and has been documented as a parasitoid of larval Lycaena xanthoides, representing a new host record reported in 2007. Like other members of the genus Cotesia, it is presumed to use polydnaviruses to suppress host immune systems, though this specific mechanism has not been directly confirmed for C. theclae.
Echinargus isola
Reakirt's Blue
Echinargus isola, commonly known as Reakirt's Blue, is a small butterfly in the family Lycaenidae. The species is native to Central America and the extreme southern United States, with regular northward migrations throughout most of the U.S. reaching nearly to the Canadian border. It has been documented visiting flowers of White Prairie Clover (Dalea candida) in Colorado, where multiple individuals may congregate on single blossoms. Very rare vagrant records extend into the southern prairies of Canada.
Hemiargus ceraunus
Ceraunus blue
A small Neotropical lycaenid butterfly found across the southern United States, the Caribbean, and through Central America to South America. Adults are active year-round in southern Florida and Texas, with peak activity in late summer elsewhere. The species occupies open, disturbed habitats and is frequently observed feeding at flower nectar. Larvae develop on flowers and seedpods of woody legumes.
Leptotes marina
Marine Blue, Striped Blue
Leptotes marina is a small butterfly in the family Lycaenidae, commonly known as the Marine Blue or Striped Blue. Adults have a wingspan of 22–29 mm with blue uppersides and brown-banded undersides marked with two blue spots on the hindwings. The species occurs from South America through Mexico to the southern United States, with adults active year-round in the south and from April to September in northern populations. Larvae feed on a diverse range of leguminous plants including Astragalus, Prosopis, and Wisteria.
Lycaena dorcas florus
Lycaena dorcas florus is a subspecies of copper butterfly described by W.H. Edwards in 1884. It belongs to a genus of butterflies commonly known as coppers, characterized by their orange-copper wing coloration. The subspecies is currently classified under the genus Epidemia, though historically placed in Lycaena. Like many grassland-associated butterflies, it faces pressures from habitat loss and climate change.
Ministrymon janevicroy
Vicroy's Ministreak, Pebbly Ministreak
Ministrymon janevicroy, commonly known as Vicroy's Ministreak or Pebbly Ministreak, is a small lycaenid butterfly discovered in 2013 by Jeffrey Glassberg. The species remained unrecognized in museum collections for over a century due to its close resemblance to the Gray Ministreak (Ministrymon azia). It is distinguished by its distinctive olive-green compound eyes, a unique feature among North American butterflies. The species occurs from southern Texas through Central America to Costa Rica, with disjunct populations on Caribbean islands.
Parrhasius m-album
white M hairstreak, White-M Hairstreak
Parrhasius m-album is a small hairstreak butterfly (wingspan 32–41 mm) with metallic blue upper wings and a distinctive silver underside marked by an M-shaped pattern. Females are larger than males. The species is strongly associated with oak habitats throughout the southeastern and central United States.
Plebejus acmon
Acmon Blue
Plebejus acmon, commonly known as the Acmon Blue, is a small butterfly in the family Lycaenidae. It is found across western North America and is frequently encountered in diverse habitats from lowland areas to montane regions. The species is known to utilize various lupine species and other legumes as larval host plants. Adults are active spring through fall depending on elevation and region, with multiple generations produced annually in warmer areas.
Plebejus icarioides
Melissa blue, Fender's blue
Plebejus icarioides is a species of lycaenid butterfly commonly known as the Melissa blue. The species has been observed colonizing alfalfa in the Great Basin region, representing a notable host range expansion. One subspecies, P. icarioides fenderi (Fender's blue), is federally endangered in the United States and has been the focus of intensive conservation research. The species exhibits ant tending behavior, with caterpillars producing sugar secretions that ants collect in exchange for protection from natural enemies.
Plebejus idas
Idas blue, northern blue
Plebejus idas is a small blue butterfly in the family Lycaenidae, widely distributed across the Palearctic and Nearctic realms. Males display iridescent blue upper wings, while females are brown with orange submarginal spots. The species exhibits notable geographic variation in its ecological relationships, including facultative versus obligate myrmecophily. The critically endangered subspecies P. idas lotis (lotis blue butterfly), native to coastal California, is believed extinct since 1994.
Plebejus idas aster
Idas Blue, Northern Blue
Plebejus idas aster is a subspecies of the Idas Blue butterfly, a small lycaenid found in North America. It belongs to a complex of closely related blue butterflies that have been subject to taxonomic revision, with this subspecies sometimes treated under the genus Lycaena. The species is associated with open habitats and has documented relationships with host plants and ants.
Plebejus lupini monticola
Plebejus lupini monticola is a subspecies of blue butterfly in the family Lycaenidae. It was described by Clemence in 1909 and is currently treated as a synonym of Plebejus monticola. The taxonomic status reflects ongoing revisions within the Plebejus genus, which includes several closely related species and subspecies of lycaenid butterflies found in western North America.
Plebejus melissa
Melissa Blue
The Melissa Blue (Plebejus melissa) is a small butterfly in the family Lycaenidae, native to western North America. This species has been extensively studied for its colonization of alfalfa as a novel host plant, representing a well-documented case of host range expansion. The Karner blue (P. m. samuelis), described by Vladimir Nabokov, is a federally endangered subspecies restricted to oak savanna and pine barren habitats in the upper Midwest.
Satyrium edwardsii
Edwards' Hairstreak
Satyrium edwardsii, the Edwards' Hairstreak, is a butterfly in the family Lycaenidae. It occurs in eastern North America from the United States into southern Canada. Larvae feed on Quercus species, particularly scrub oak (Q. ilicifolia). The species has been documented as endangered in some regions and exhibits myrmecophilous associations with ants.
Satyrium titus
Coral Hairstreak
Satyrium titus, the coral hairstreak, is a tailless North American butterfly in the family Lycaenidae. It is distinguished from other hairstreaks by the absence of tail-like projections on the hindwings and a distinctive row of red-orange spots on the underside of the hindwing. Adults frequent open, brushy habitats and are often observed nectaring at butterfly weed and other flowers. Caterpillars feed primarily on the fruits of wild plums, cherries, and related woody plants in the genera Prunus, Amelanchier, and Quercus.
Strymon melinus
Gray Hairstreak
Strymon melinus, the Gray Hairstreak, is a small lycaenid butterfly widespread across North America. Males exhibit density-dependent mating tactics, defending perches on hilltops at low densities and switching to patrolling behavior when intruder numbers increase. The species thrives in weedy, disturbed habitats and urban environments, with a notably long flight season from February to November at low elevations. It is considered stable or increasing in parts of its range, including California's Central Valley.