112 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Aeronautes melanoleucus (Baied). 



White-throated Swift. 



Cypselus saxatilis Belding, Proc. U. S. Nat. Mus., V. 1883, 547 (San Jose del 



Cabo; San Jose). 

 Micropus melanoleucus Bryant, Proc. Calif. Acad. Sci., 2d ser., II. 1889, 288 (San 



Jose del Cabo). 



Two specimens, both males, taken on May 19 on the Sierra de la Laguna, 

 are slightly smaller than the average of my Colorado examples, but are other- 

 wise similar to the latter. 



On the Sierra de la Laguna, during May and the first week in June, Mr. 

 Frazar saw these Swifts almost daily, but never in very great numbers. They 

 were usually observed flying along the sides of the mountain, and only once 

 over its summit. The sexual organs of two males shot on May 19 were at 

 the maximum stage of development, but Mr. Frazar obtained no other evi- 

 dence that the species breeds in these mountains, nor did he find it elsewhere in 

 Lower California. Mr. Belding, however, noted it at San Josd del Cabo on 

 April 29, 1882. 



The range of the White-throated Swift extends from California to Central 

 America. It breeds at many places in the mountains of California as far 

 south as San Bernardino. 



Calypte costas (Bocrc). 

 Costa's Hummingbird. 



Calypte costae Belding, Proc. U. S. Nat. Mus., V. 1883, 542 (Cape Region; San 

 Jose ; Cape St. Lucas; Miraflores), 547 (breeding at La Paz) ; VI. 188-3, .348 

 (Victoria Mts.). Ridgwat, Ibid., V. 1883, 542 (descr. nests and eggs) ; Rep. 

 U. S. Nat. Mus., 1889-1890, 1891, a37-339, pi. 39 (Cape district of Lower 

 Calif. ; figures female and nest from La Paz). 



Trochilus costae Bryant, Zoe, II. 1891, 191 (San Jose del Cabo). 



Lower California specimens do not appear to be in any way peculiar. 



Individual variations : — Adult males. The amount of green on the back, 

 sides, and abdomen is somewhat variable, and the length of the bill exceedingly 

 so. Most of my specimens have the purplish of the forehead obscured by what 

 appears to be a thin coating of pollen. In one taken at La Paz on February 

 24, 1887, the forehead and throat are covered with pin feathers. 



Immature males. A male killed at La Paz on February 23, 1887, diff^ers from 

 the adult female only in having the plumage of the top and sides of the head 

 browner and interspersed with a few (three or four) purple feathers. It is 

 evidently a bird of the preceding year. 



