The mountaingems are the Lampornis genus of hummingbirds which inhabit mountainous regions from the southwestern United States to the Isthmus of Panama. These are medium-sized to large (10–13 cm) hummingbirds with shortish slightly curved black bills. The males typically have green upperparts and a brightly coloured throat, which is a dull colour in the female. The females of some species also may differ significantly from the males in other plumage features. The female mountaingem is entirely responsible for nest building and incubation. She lays two white eggs in a deep plant-fibre cup nest. Incubation takes 15–19 days, and fledging another 20-26.