''Euphilotes ancilla'', the Rocky Mountain dotted blue, is a species of

butterfly Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The group comprises ...

of the family

Lycaenidae Lycaenidae is the second-largest 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 the known butterfly ...

. It is found from Washington south to California and southern Alberta and Saskatchewan south through the Rockies and high plains to Wyoming, Colorado, Utah, and northwestern New Mexico. The species was first described by William Barnes and

James Halliday McDunnough James Halliday McDunnough (10 May 1877 – 23 February 1962) was a Canadian linguist, musician, and entomologist best known for his work with North American Lepidoptera, but who also made important contributions about North American Ephemerop ...

in 1918. Its wingspan is from 17 to 23 mm. Its habitats include sun-exposed rocky slopes and flats with host plant colonies. Larvae feed on various ''

Eriogonum ''Eriogonum'' is a genus of flowering plants in the family Polygonaceae. The genus is found in North America and is known as wild buckwheat. This is a highly species-rich genus, and indications are that active speciation is continuing. It inc ...

'' species, especially sulphur-flower.

References

{{Taxonbar , from=Q3060398 Butterflies of North America Euphilotes Butterflies described in 1918