PETROCHBLIDON. 289 



dulness of the frontal band. There is no appreciable difference in 

 the sexes. 



A specimen in Mr. Lawrence's collection, from Panama, I cannot 

 distinguish, except in being smaller. Length, 4.80; wing, 4.10; 

 tail, 2.10. The forehead is nearly white, as usual in lunifrons.^ 



Summer specimens from the southern Rocky Mts. (Los Pinos, 

 N. M.) and Carlisle are considerably smaller than those from Fort 

 Bridger. 



Specimens in the collection from throughout the whole United 

 States to northern border, as also — 



' Petrochelidon . 



?Hirmdo americana, GrMBLis, S. N. I, 1788, 1017 (from Bufifon, VI, 698, 

 La Plata). — Petrochelidon americana, Cab. Mus. Hein. 1850-1, 47. 

 ?Hirundo pyrrhonota, Vieill. Encycl. Meth. II, 524 (Azara, Apunt. II, 

 511, no. 305, Paraguay). — Cotyle p. Bhkm. Keise La Plata, II, 1861, 

 477 (Tucuman). 

 Hab. Brazil? Paraguay? 



In Mr. Lawrence's collection is an immature bird (No. 148, from Brazil), 

 muoli like corresponding stages of P. lunifrons, but differing in considerably 

 smaller bill, and in the lower tail coverts being much shorter (falling three- 

 quarters of an inch short of the tip). The rufous of the rump extends further 

 up the back, and there is a decided wash of reddish over the breast and belly, 

 sides and crissum, leaving only the abdominal region pure white. The frontal 

 band is not fully developed, but seems as if it might be whitish ; there is a 

 blackish spot on the lower throat, and a few whitish feathers in the chin. The 

 chestnut of the throat is lighter than in lunifrons, or of about the same shade 

 as that of rump. I think there is no doubt of its being quite distinct from 

 lunifrons or swainsoni, but in its still immature condition cannot venture to 

 identify it. There are two names to which it might be referred, the H. ameri- 

 cana, of Gmelin — P. americana, Cab. M. Hein. I, 47 — (based on Hirondelle a 

 croupion roux, etc. (from the La Plata), Buffon, Ois. VI, 698, La Plata) — 

 which, however, appears much too large — and Hirundo pyrrhonota, Vieill. 

 Encycl. II, 524; Azara, Apunt. II, 511, Sonnine ed. 104; Cotyle pyrrhonota, 

 Burm. La Plata, II, 477. This is described by Azara as having black crissum ; 

 Burmeister, however, says this is grayish, edged with rusty whitish ; the fore- 

 head, lores, cheeks, and rump rusty brownish-red ; fore-neck, breast, and belly 

 ash gray, washed with yellowish, and tinged with reddish about the anus. 

 Length, 5". Wings, 4". 



Buffon speaking of his Hirondelle a croupion roux et queue carr(e, describes 

 it as brownish-black above, with green and blue reflections ; rump rufous, the 

 feathers edged with whitish ; under parts dull white, the lower tail coverts 

 rufous. Another specimen is said to have a rufous throat. No mention is 

 made of a black spot on the jugulum, or of a frontal band. 



19 May, 1865. 



