TACHYCINETA. 235 
Supra chalybeo-viridescens, alis caudaque nigricantibus, illis intus tenuissime albo terminatis ; Subtus albus; 
rostro nigro, pedibus corylinis. Long. tota 5-7, ale 5°7, caudx rectr. med. 2°0, rectr. lat. 2°4, rostri a 
rictu 0-6, tarsi 0°45. (Descr. maris ex Duefias, Guatemala. Mus. nostr.) 
Hab. Norra America from Alaska and Great Slave Lake to Arizona &e.4, Bermuda 4. 
—Mexico (Deppe'*), Matamoras (Couch? 3), Mazatlan (Grayson), Plateau of 
Mexico (Sumichrast®, le Strange), San Jose (Sallé*), Jalapa (de Oca™), Orizaba 
(Sumichrast*), Pine ridge above Mirador (Sartorius*); Guaramaua (Skinner ®), 
Vera Paz 3, Duefias, Pajal Grande, San Gerdnimo (0. 8. & F. D. G.).—CUBA. | 
This species appears to be commoner in the eastern than in the western States, 
though found over nearly the whole of North America during the breeding-season :’ 
during the winter, however, large numbers remain in Florida; others pass to Cuba, 
Mexico, and Guatemala. 
There is no positive evidence of the species breeding in Mexico, though it is included 
by Prof. Sumichrast amongst the resident birds of the Plateau of Mexico, and a speci- 
men was obtained by Dr. Sartorius in the pine-region above Mirador, in the month 
of June ®. 
In Guatemala it is a winter visitant to the tablelands and to the neighbourhood of 
San Geronimo in Vera Paz, where it is frequently found associating with 7. thalassinus. 
The habit of this species to congregate in vast flocks has often been alluded to by 
writers on North-American ornithology 14. We once observed a flock of this kind in 
the open space in the forests of the Volcan de Fuego called Pajal Grande, the elevation 
of which is about 5000 feet above the sea-level. ‘This was on the 25th December 1873, 
when a vast flock of these birds were seen circling round and round in a compact mass, and 
every now and then settling on some low shrubs, weighing down the outer boughs and 
crowding together like a swarm of bees. We could detect no object in this assemblage ; 
it was neither the season of migration, nor was it the roosting-time, as it took place in 
the afternoon of a bright sunny day. 
In Cuba, Dr. Gundlach includes 7. bicolor amongst the regular winter visitants to 
the island, where it arrives later than Hirundo erythrogaster, remains the winter, and 
leaves again for.the north in April. 
It breeds in holes in trees and in stumps, making a nest of fine soft hay, thickly 
lined with feathers. The eggs are, like those of Z. thalassinus, white 1. 
3. Tachycineta albilinea. (Hirundo albilinea, Tab. XV. fig. 1.) 
Petrochelidon albilinea, Lawr. Ann. Lye. N.Y. viii. p. 2+; Scl. & Salv. P.Z.S. 1864, p. 3477, 
Tachycineta albilinea, Lawr. Mem. Bost. Soc. N. H. ii. p. 271°. 
Hirundo albilinea, Baird, Rev. Am. B. i. p. 800‘; Zeledon, Cat. Av. Costa Rica, p. 5°. 
Petrochelidon leucoptera, Lawr. Ann. Lyc. N. Y. vii. p. 817° (nec Gm.). 
Petrochelidon littorea, Salv. P. Z. S. 1863, p. 189"; Ibis, 1866, p. 192°. 
30* 
