Hirundapus is a genus of the swift family of birds in the family Apodidae, of the order Apodiformes.

1/ Silver-backed needletail (Yến đuôi cứng bụng trắng, Hirundapus cochinchinensis)

2/ White-throated needletail (Yến đuôi cứng họng trắng, Hirundapus caudacutus), also known as needle-tailed swift or spine-tailed swift
The specific name caudacutus comes from the Latin words cauda meaning "tail" and acutus meaning "pointed".

3/ Brown-backed needletail (Yến đuôi cứng lớn, Hirundapus giganteus), or brown needletail

As the name apodiforme—meaning "footless" in Greek—suggests, the legs of hummingbirds, swifts and treeswifts (or 'crested' swifts) are rather small and offer limited functional uses.
The family name, Apodidae, is derived from the Greek ἄπους (ápous), meaning "footless", a reference to the small, weak legs of these most aerial of birds.

The genus name Hirundapus is constructed from the names of the swallow genus Hirundo and the swift genus Apus.
Hirundo is a Latin word meaning swallow.
The word apus is Latin and derived from the Ancient Greek α, a ("without") and πளுக்கான, pous ("foot"), meaning "footless". 
The English name needletail is from the spined or thorny tail ends.