of the United States. 63 



Wings extremely long; first primary a little shorter than 

 the second, which is longest. Tail of ten feathers. 



Female and young hardly differing from the adult male. 

 Moult annually. 



Build in clefts of high rocks and buildings; nests con- 

 structed of small twigs, agglutinated together by a viscous 

 substance secreted in the mouth. Flight horizontal and very 

 rapid ; rise from the ground with difficulty on account of 

 their very short feet: cling firmly by their claws. 



Spread all over the globe. 



70. Cypselus pelasgius, Temm. Deep sooty-brown ; chin and 

 line over the eye dull whitish ; wings extending one and a 

 half inches beyond the tail ; tail even, feathers mucronate. 



Chimney Swallow, Hirundo pelasgia, fVils. Am. Orn. v. 



p. 48. pi. 39- fig. 1. 



Inhabits chimneys in all the United States during summer : 

 common : does not extend very far north. 



15. HIRUNDO. 



Hirundo, L. Briss. Gm. Lath. 111. Cuv. Vieill. Temm. 

 Ranz. 



Bill triangular, cleft nearly to the eyes, with a few scat- 

 tered bristles at the base ; upper mandible notched ; lower 

 shorter, a little narrower, acute, and nearly straight to the 

 tip : nostrils basal, oblong, posteriorly closed by a mem- 

 brane, and covered by the frontlet feathers : tongue short, 

 cartilaginous, bifid at tip. Tarsus short, slender ; middle 

 toe longer than the subequal lateral ones, united with 

 the outer to the first articulation ; inner toe free, generally 

 longer than the hind toe, which is not versatile : middle toe 

 nail largest. First primary longest. Tail of twelve feathers, 

 almost always forked. 



Female and young often resemble the adult male. Moult 

 annually. 



