The genus is assigned to the subfamily Polytminae which is sometimes referred to by the informal name "mangoes".

The genus Heliothryx was introduced in 1831 by the German zoologist Friedrich Boie.

[1] Boie did not specify the type species but this was designated as the black-eared fairy by George Robert Gray in 1840.

[4] The genus contains the following two species:[5] Heliothryx hummingbirds are vibrant, medium-sized birds of tropical lowlands, favoring forest edges, clearings, and gardens.

They have emerald-green upperparts, snow-white underparts, and white tail feathers, with sharp black bills perfectly designed to extract nectar.