What is "basileuterus"

Basileuterus is a genus of New World warblers, best represented in Central and South America. This is one of only two warbler genera that are well represented in the latter continent. Some species formerly considered in this genus are now placed in the genus Myiothlypis. It is likely that the ancestors of this genus colonised South America from the family’s heartland in northern Central America even before the two continents were linked, and subsequent speciation provided most of the resident warbler species of that region.

These are mainly robust warblers with a stout bill. The majority of species have olive or grey upperparts and yellow underparts. The head is often strikingly marked with a long broad supercilium, a coloured crown or crown stripes, and often other striking head markings.

Many species are not well-studied, but those for which the breeding habits are known all build a domed nest on a bank or on the ground, so this is presumably typical of the genus as a whole.