Today most authorities consider the two taxa in this genus as separate species, but some (e.g. AOU) continue to treat them as conspecific, in which case scitulus is a subspecies of T. polytmus.

The genus Trochilus was introduced in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae.

[1] The genus name is from the Ancient Greek τροχιλος/trokhilos, a small unidentified bird mentioned by Aristotle.

[3][4] In his Systema Naturae Linnaeus included 18 species of hummingbird all of which he placed in Trochilus.

Today, 12 of these species are still recognised, but only the red-billed streamertail is retained in its original genus.