BIRDS OF NORTH AND MIDDLE AMERICA. 687 



Genus AERONAUTES Hartert. 



Aeronautes (I Hartert, Cat. Birds Brit. Mus., x\'i, 1892, 459. (Type, CijpseJus 

 melanoleucus Baird.) 



Medium-sized Cypselinne (length, about 135-152 mm.) with toes 

 (as well as tarsus) feathered, outer and middle toes directed forward 

 on line with axis of tarsus, tail forked for less than one-fourth its 

 length, and feathers of pileum and under parts distinctly outlined 

 (broadly rounded). 



Tail about half as long as wing, moderately forked (for less than 

 one-fourth its length), the lateral rectrices not attenuated terminally, 

 the outermost pair little if any longer than next pair; tenth (outer- 

 most) primary shorter than ninth, but equal to or longer than eighth; 

 feet very stout, the toes short and thick and claws strong; tarsi and 

 toes feathered (except on soles of latter) ; middle toe slightly longer 

 than tarsus, but scarcely longer than inner toe, which is slightly 

 longer than the outer; hallux very short, inserted laterally on inner 

 side of foot. 



Coloration. — Dusky above and on lateral under parts; throat, chest, 

 median line of breast and abdomen, and a patch on upper flanks 

 or sides of rump, dull white. 



Nidiji cation. — Nest placed in crevices of vertical cliffs or walls of 

 old buildings, composed of feathers, bark, grass, wool, cotton, etc., 

 glued to its support by salivary excretion. 



AERONAUTES MELANOLEUCUS (Baird). 



WHITE-THROATED SWIFT. 



Adults (sexes alike). — Pileum and hindneck grayish brown to very 

 dark sooty brown, sometimes uniform but usually becoming paler on 

 forehead, and with feathers indistinctly margined with jmler, espe- 

 cially on frontal region, the projecting edges of crown dull whitish, 

 forming a distinct narrow superciliary streak ; back, scapulars, wing-cov- 

 erts, rump, and upper tail-coverts plain sooty blackish, the tail similar 

 but rather more sooty (less blackish); a large patch of white or 

 brownish wliite on each side of rump, more or less pointed anteriorly; 

 remiges dark sooty brown or sooty blackish, the secondaries broadly 

 tipped on outer web with dull or brownish white, the inner wobs of 

 primaries passing into pale grayish brown on edges (except on longer 

 quills); a dusky spot immediately in front of eye, the loral region 

 otherwise whitish; auricular and postocular regions sooty grayish 

 brown; suborbital and malar regions, chin, throat, chest, and median 

 portion of breast and abdomen white (usually dull or more or less 

 tmged with browmish); sides and flanks (broadly) and under tail- 

 coverts plain Yevy dark sooty brow^i or sooty black; feathers along 



tt ^Atjp, air; vaoTTjr, a sailor. (Richmond.) 



