.• 



210 



REVIEW OF AMERICAN BIRDS. 



[part I. 



r . 



n 



and crissuin, and usually forehead, rufous ; 



belly white 



Edge of wing smooth. Tarsua longer than In last; 

 equal to middle toe and half the claw. Nostrils 

 bordered along posterior half by membrane, but 

 not overhung internally. Bill very small. Tail 

 forked. Crissum duskj', except Neochelldon fucatu. 

 Basal and whole of next joint of middle toe ad- 

 herent externally to outer tfoe. Tail very 

 deeply forkwl. 



Tarsus feathered at upper end internally 



Basal and half the next joint of middle toe ad- 

 herent externally to outer toe. 



Tarsus entirely bare .... 



Tarsus with feathers on inner face at 

 upper end 



Basal joint only of middle toe adherent ex- 

 ternally, and free at extreme end. 



Tibial joint covered with feathers which 

 extend a short distance along inner 

 face of tarsus 



Edge of wing armed with stiflf recurved hooks. Tarsus 

 as in preceding (tarsus and toes much as in Pyijo- 

 chelidon). Bill larger and more depressed. Tail 

 emarginate only. Crissum white . . 



Nostrils lateral ; bordered behind and inside, or overhung by 

 membrane, the outer edge of which is straight, and di- 

 rected either parallel with axis of bill or diverging from it. 

 Tarsus short ; about equal to middle toe without claw. 

 Tibial joint feathered ; feathers extending along 

 inside of upper end of tarsus. 



Tarsus bare at lower end. Lateral claws reach- 

 ing only to base of middle. 

 Tail very deeply forked, much longer than 

 closed wings ; lateral feathers linear, 

 and very narrow at end, twice the 

 length of central. Upper pan. and 

 pectoral collar steel blue ; front and 

 throat, sometimes under parts, rufous. 

 Tail feathers with large spots . 

 Tail with shallow fork, not exceeding half 

 an inch, shorter than closed wings. 

 Feathers broad. Color blue or green 

 above, with or without white rump ; 

 whiie beneath 



Tarsus with a tuft of feathers at lowei end. 



Petrochelidon 



Atticora. 



Notiochelidon, 

 Neochelidon, 



Pygochelidon, 



Stelgidopteryx, 



ITirundo. 



Tachycimta, 



