CHAPTEE XIV.— SWALLOWS 



eam. hirundinidj: 



Chaes. — Swallows are Jissirostral Oscine Passeres with nine 

 primaries. — Bill short, broad, flat, somewhat triangular, deeply 

 cleft, the gape wide and about twice as long as the culmen, the 

 mouth thus opening to about beneath the eyes. This is the 

 strongest character of the family in comparison with its Oscine 

 allies, and one perfectly distinctive, though some genera of 

 Hirundines, especially Progne, approch the Ampelidce in the 

 form of the bill. The bill narrows rapidly to the compressed 

 acute tip. Nasal fossse short and wide; nostrils directed later- 

 ally or upward, sometimes circular and completely exposed, 

 sometimes scaled over. Culmen convex, scarcely a third as 

 long as the head ; tip of upper mandible overhanging, usually 

 nicked. Eictus smooth (or with a few inconspicuous bristles?). 

 Wings extremely long and strong, the pinion bearing only nine 

 primaries, the first of which equals or exceeds the second in 

 length, the rest being so rapidly graduated that the ninth is 

 scarcely or not half as long as the first ; secondaries and 

 their coverts also very short ; all these quill-feathers broad and 

 stout. An acute, thin-bladed, and somewhat falcate wing, of 

 surpassing volatorial power, results from these modifications. 

 Tail of 12 rectrices, perhaps abnormally only 10, usually forked, 

 or at least emarginate, and often deeply forficate, the outer- 

 most feathers being in this latter case narrowly linear in shape 

 for a considerable distance. Feet short, small, and weak, ill- 

 adapted to secure foothold, and very badly formed for walking 

 — Swallows scarcely use their feet for locomotion, relying 

 mainly upon their prowess of pinion. The tarsal envelope 

 thoroughly Oscine in structure, being scutellate in front and 

 laminate behind ; it is sometimes partially, or almost entirely 

 feathered; the tarsi are commonly shorter than the lateral 

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