112 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Aéronautes melanoleucus (Bairp). 
WHITE-THROATED SWIFT. 
Cypselus saxatilis Betptnc, Proc. U. 8. Nat. Mus., V. 1883, 547 (San José del 
Cabo; San José). 
Micropus melanoleucus BRYANT, Bide: Calif. Acad. Sci., 2d ser., II. 1889, 288 (San 
José 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 José 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 costae (Botrc.). 
Costa’s HUMMINGBIRD. 
Calypte costae BeipinG, Proc. U.S. Nat. Mus., V. 1883, 542 (Cape Region; San 
José; Cape St. Lucas; Miraflores), 547 (breeding at La Paz); VI. 1883, 348 
(Victoria Mts.). Ripeway, Jbid., V. 1883, 542 (descr. nests and eggs); Rep. 
U. S. Nat. Mus., 1889-1890, 1891, 337-339, pl. 89 (Cape district of Lower 
Calif.; figures female and nest from La Paz). 
Trochilus costae Bryant, Zoe, II. 1891, 191 (San José 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, differs 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. 
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