Euphonias are members of the genus Euphonia, a group of Neotropical birds in the finch family. They and the chlorophonias comprise the subfamily Euphoniinae.
The genus name is of Greek origin and refers to the birds' pleasing song, meaning "sweet-voiced" (εὖ eu means "well" or "good" and φωνή phōnē means "sound", hence "of good sound").
Most male euphonias are dark metallic blue above and bright yellow below. Many have contrasting pale foreheads and white undertails. Some have light blue patches on the head and/or orangish underparts. Females much more plain, predominantly olive-green all over. They range in overall length from 9 to 11 cm (3+1⁄2 to 4+1⁄2 in). They eat small fruit and berries, particularly mistletoe (Loranthaceae). Some species may also eat some insects.
Euphonias were once considered members of the tanager family, Thraupidae. A molecular phylogenetic study of the finch family Fringillidae published in 2012 included 9 species from the genus Euphonia and a single species from the genus Chlorophonia, the blue-naped chlorophonia. The resulting cladogram showed the blue-naped chlorophonia nested within the Euphonia clade implying that the genus Euphonia is paraphyletic. The genus was introduced in 1806 by the French zoologist Anselme Gaëtan Desmarest in his Histoire naturelle des tangaras, des manakins et des todiers with the white-vented euphonia as the type species.
