MICROPUS. 303 
tical-ovate, plain pure white. Hab. Eastern North America, north 
to Labrador and to 50° in the interior, west to edge of Great 
Plaine sisciieesavesvconteses 423. C. pelagica (Liny.). Chimney Swift. 
b%. Wing decidedly less than 5.00. 
c. Rump, upper tail-coverts, and tail light sooty grayish, very much 
lighter than the olive-dusky back; breast and belly light sooty 
grayish; length about 4.15-4.50, wing 4.30-4.75, tail (including 
spines) 1.50-1.90. Nest like that of C. pelagica, but only (?) in hol- 
low trees. Higgs .71 X 49. Hab. Western United States (chiefly 
Pacific coast), north to British Columbia; south, in winter, to 
Guatemala.......ccececsseeeees 424, C. vauxii (Towns.). Vaux’'s Swift. 
ce’. Upper parts entirely blackish (very slightly paler on rump, etc.), glossed 
‘with olive-greenish on back and with bluish on wings; breast and 
belly deep sooty grayish brown; wing 4.20-4.60, tail (including 
spines) 1.70-1.75. Hab. Southern Mexico (Yucatan, including 
Cozumel, Tehuantepec, etc.), Guatemala, and south to Costa Rica. 
C. gaumeri Lawr. Gaumer’s Chimney Swift.? 
a, Throat not paler than rest of under parts; male with a broad collar of rufous 
round neck; length about 4.75-5.00, wing 4.80-5.20, tail 1.80-2.10. Hab. Cen- 
tral America, north to eastern Mexico (Orizaba), south to Ecuador. 
C. brunneitorques Larr. Lafresnaye’s Chimney Swift.’ 
Genus AERONAUTES Hanrrerr!‘ (Page 302, pl. LXXXIX., fig. 4.) 
Species. 
Above dull blackish, usually becoming lighter and grayer on forehead; sides 
and under tail-coverts also dull blackish; other lower parts, tips of secondaries 
(outer webs only), and a patch on each side of rump, white; length 6.50-7.00, wing 
5.30-5.90, tail 2.50-2.70. Hab. Western United States (in mountains), and south to 
Guatemala....ccccccssesereres 425. A. melanoleucus (Barrp). White-throated Swift. 
Famity TROCHILIDAZ.—Tue Hummincsirps. (Page 297.) 
(Nest a beautifully felted cup-shaped structure, composed of plant-down, 
spiders’ webs, lichens, etc.—the last exteriorly, the first internally. Eggs 2, ellipti- 
cal-ovate or elliptical-oval, large in proportion to size of the bird, plain pure white.) 
Generas 
a. Anterior toes united for basal half; bill much compressed (except at base), about 
1 These spines usually worn entirely off in Yucatan specimens. 
2 Chetura gawmert Lawr., Ann. N. Y. Ac. Sci. ii. No. 8, March, 1882, 245, 
8 Chetura brunneitorques Larr., Rev. Zool. 1844, 81. 
4 Aéronautes Hartert, Cat. B, Brit. Mus. xvi. 1892, 459. Type, Cypeelus melanoleucus Barrp. 
5 Characters of all the Mexican genera are given, for the reason that almost any species of Hummingbird 
found on the table-lands or mountains of Mexico may reasonably be expected to occur within our borders. In 
