Medium-sized Amazonian hummingbird with amazing tail. Male has blue crest-like cap. Blue gorget and black line down centre of breast and belly. Rest of underparts white with green sides of breast and belly. Above mostly bronzy-brown. Lateral tail feathers very long, bare and ending in large, dark rackets. Two central feathers long and narrow.
There are recent records of this species from just two locations and the known range is very small.