''Echinargus isola'', or Reakirt's blue, is a

butterfly Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

of the family

Lycaenidae Lycaenidae is the second-largest family (biology), family of butterflies (behind Nymphalidae, brush-footed butterflies), with over 6,000 species worldwide, whose members are also called gossamer-winged butterflies. They constitute about 30% of ...

. It is the sole representative of the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Echinargus''. It is found in Central America and the extreme southern U.S. ''Echinargus isola'' migrates regularly throughout most of the U.S. almost to the

Canada–United States border The international border between Canada and the United States is the longest in the world by total length. The boundary (including boundaries in the Great Lakes, Atlantic, and Pacific coasts) is long. The land border has two sections: Canada' ...

, and very rarely into the southern prairies. The

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

is 16–23 mm. Adults are on wing from June to October in the north and year round in south.Reakirt's Blue
Butterflies of Canada Its habitats include fields, gardens, open areas, and host plants. The larvae feed on

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

, particularly mesquites (''

Prosopis ''Prosopis'' is a genus of flowering plants in the family Fabaceae. The current circumscription of the genus contains three species found in northern Africa, the Middle East, Central and South Asia. Previously it also contained around 40 species ...

'' species). Adults feed on flower nectar from spearmint, white sweet clover, and a variety of other herbs.

Subspecies

*''Echinargus isola isola'' *''Echinargus isola alce'' (Edwards, 1871) (Colorado)

References

{{Taxonbar, from=Q13602601 Polyommatini Butterflies of North America Taxa named by Tryon Reakirt Butterflies of Central America