This species has been separated from Hirundo as a genus (Hypurolepis of Gould) on account of its short, slightly forked tail. The difference is only one of degree and I cannot see any necessity for the division; to be consistent one would have to again separate Hirundo smithii on account of its longer tail and again H. daurica on account of other minute structural differences.
The species also has been much split, probably on insufficient data and the material in the British Museum does not support the separation into more than two races, though Oberholser's H. j. abbotti from the Anamba Islands may have to be kept separate on account of its larger size. Birds from the Philippines, Malay Peninsula, Burma and the Andamans seem to have paler chestnut throats and foreheads than those from Java, Borneo, Sumatra and Palawan but there is so much overlapping that I cannot discriminate between, them.
Key to Subspecies.
A. Upper plumage glossed with purple-blue bill much larger…………H. j. javanica, p. 243.
B. Upper plumage glossed with green, bill much smaller…………H.j. domicola, p. 244.