whiter than in the summer plumage, there heing much less of the ashy-brown shade on the breast 

 and sides, while the dusky shaft-lines are almost entirely obscured. 



The winter plumage is also more steel-green than the summer dress, the wearing of the feathers 

 being accompanied by a steel-blue lustre in the place of the green. 



This is a smaller species than T. leucorrhous , of which it is the northern representative. The 

 white band across the rump is much narrower and has the dusky shaft-lines, the feathers adjoining 

 the upper tail-coverts having a green or a dusky spot at their ends. There is none of the brown 

 mottling which appears on the immature bird of T. leucorrhous. The chest has also some dusky 

 shaft-lines, which are, however, often scarcely traceable, and are never so distinct as on the 

 rump. 



In the Sclater collection, now in the British Museum, is a specimen of Hirundo leucopygia of 

 Taczanowski, received in exchange from the Warsaw Museum. The specimen in question seems 

 to us to be undoubtedly a young bird. The under surface is washed with smoky brown, the 

 green colour of the upper surface is duller, and the quills and tail are sooty brown, with very 

 broad white margins to the inner secondaries. The u]3per tail-coverts are smoky brown, with 

 distinct dusky blackish shaft-lines. The white rump-band is very narrow, but plainly marked with 

 blackish shaft-lines. 



If we are correct in believing this to be the immature plumage, it seems to prove that the white 

 margins on the inner secondaries are a sign of immaturity, and it is certain that they become 

 absolutely abraded in bi'eeding birds. 



The following are the measurements of the series in the British Museum, for comparison with 

 the specimens of T. leucorrhous : — 



Total length. Culmen. Wing. Tail. Tarsiis. 



in. in. in. in. in. 



cJ ad. Vera Cruz, Mexico {A. Boucard) . . . 4-3 0-35 3-7 1-65 0-35 



Ad. Progreso, Yucatan {E. Devis) 4-5 0-35 3-85 1-65 0-4 



c? ad. Belize, Honduras (0. Sa/ym) 4-5 0-4 3-75 1-65 0-4 



cJ ad. Punta Arenas, Costa Rica (0. S.) . . . 4-8 0-4 3-9 1-9 0-4 



Ad. Guatemala {O. S.) 4-4 0-35 3-8 1-7 0'4 



? ad. Chiapam, Guatemala (0. S.) 4-5 0-4 3-7 I'o 0-4 



Ad. Panama [M'Leannan) 4-0 0-35 3-65 1-55 0-4 



(^ ad. „ „ 4-3 0-4 3-9 1-6 0-35 



Ad. „ „ 4-3 0-35 3-7 1-6 0-4 



cJ juv. Chepen, Peru (/. Stohmann) .... 4-0 0-3 3-6 1-75 0-35 



Allowing for age and condition of specimens, it will be seen that T. albilinea is a much smaller 

 bird than T. leucorrhous, the wing never exceeding 4 inches in length. 



Hab. Central America, from Mexico to Panama, reoccurring in Peru. 



The first notice of this bird appears to have been the record by Mr. G. N. Lawrence of 

 its occurrence in Panama, where it was procured by Mr. M'Leannan. Mr. Lawrence 

 first determined the species as Ilinmdo leucoptera, which is a synonym of Tachycineta 

 (dbiventris, a strictly South-American species. In 1863 Mr. Lawi*euce, detecting the 

 error in his previous identification of the Panama bird, described it as a new species 



