1891.] The Origin of the Avifauna of the Bahamas. 533 
the mainlands at Yucatan the species reappears in Vireo ochra- 
ceus, which, although decidedly smaller than the island birds, 
exactly resembles them in coloration. On the islands of Old 
Providence, 250 miles north of Aspinwall, the species again is 
found, but here is nearer the West Bahama bird, V. crassirostris. 
18. Callichelidon cyaneoviridis —Callichelidon is the only 
genus of birds peculiar to the Bahamas. That this single instance 
should be among the swallows, birds possessing great power of 
flight, and generally having extended habitats, is indeed most 
remarkable. Mr. Scott’s recent capture of this species in the 
Tortugas * is, so far as we know, the only occasion on which it 
has been found beyond the Bahamas. It has not been recorded 
from Cuba, and this is one of a number of cases where species 
which should occur there have not been recorded from that 
island. Indeed, our knowledge of Cuban birds may well be sup- 
plemented by much additional information before it can be con- 
sidered complete. As has been said, C. cyaneoviridis in its 
generic distinctness stands alone among Bahaman birds, and 
unless it is a survivor of a once more widely distributed species 
it is difficult to give even a probable theory of its origin. It has 
no near West Indian relatives, unless the very different Zachy- 
cineta euchrysea of Hayti be considered as such, and it is per- 
haps as near to Tachycineta thalassina of Northern North America 
as to any other species. 
19. Certhiola bahamensis—One of a very distinct group of 
three species of peculiar distribution. Certhola caboti, very 
closely related to bahamensis, is found in Cozumel, while the 
remaining species, C. tricolor, which inhabits the island of Old 
Providence, is nearer to bahamensis than to caboti. 
20. Geothlypis rostrata. 
21. Geothlypis coryt. 
22. Geothlypis tannerii—Three closely related forms inhabiting 
__ Tespectively the islands of New Providence, Eleuthera, and Abaco. 
_ Additional material will doubtless show, as Mr. Allen states, 
that the bird from Andros will constitue a fourth form.. This is 
the fifth and by far the most interesting instance in which an 
5 The Auk, VII., 1890, p. 265. 
