In the revised classification to create monophyletic genera, the green-and-white hummingbird was placed by most taxonomic systems in a new genus Elliotomyia.

Both sexes have a medium length straight bill with a blackish maxilla and a reddish mandible with a dark tip.

[10] The green-and-white hummingbird is found on the east slope of the Peruvian Andes discontinuously from Huánuco Department south to Cuzco, including at Machu Picchu.

[10] The white-bellied hummingbird forages for nectar at a variety of flowering plants, shrubs, and trees, though its diet is not known in detail.

It makes a cup nest of plant wool bound by spiderweb with lichen on the outside, and often places it on a horizontal branch of a small tree.

The green-and-white hummingbird's song is "a repeated short phrase of typically three squeaky notes, 'tseet-chew-chip … tseet-chew-chip ...'."