HIRUNDINID.E — THE SWALLOWS. 327 



Bill rather weaker ; commissure and culmen nearly straight to near tip. 

 Frontal feathers bristly. Tail nearly even. Throat, rump, and crissum, 

 and usually forehead, rufous ; belly white .... Petrochelidon. 



h. Edge of wing smooth. Tarsus 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 dusky 

 except in NeocheUdon fucata. Various genera and subgenera, none North 

 American, as Atticora, Notiochelidon, NeocJielidon, and Pygochelidon. 

 c. Edge of wing armed with stiff recurved hooks. Tarsus as in preceding 

 (tarsus and toes much as in P ijgochelidori). Bill larger and more depressed. 



Tail emarginate only. Crissum white Stelgidoptenjx. 



B. Nostrils lateral ; bordered behind and inside, or overhung by membrane, the 

 outer edge of which is straight, and directed either parallel with axis of bill or 

 diverging from it. 



a. Tarsus short; about equal to middle toe without claw. Tibial joint feath- 

 ered ; feathers extending along inside of upper end of tarsus. 



Tarsus bare at lower end. Lateral claws reaching 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 parts and pectoral collar steel-blue ; front and throat, some- 

 times under parts, rufous. Tail-feathers with large spots . Hirundo. 



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 ; Avhite beneath. Tail-feathers without 

 spots ........... Tachjcineta. 



Tarsus with a tuft of feathers at lower end. Lateral claws lengthened, 

 reaching beyond base of middle claw. 



Tail slightly forked. Color dull-brown above ; beneath white, 

 Avith brown pectoral collar ....... Cotyle. 



h. Tarsus long ; equal to middle toe and half claw ; entirely bare. Tail con- 

 siderably forked, about equal to closed wing. Color green above ; white 

 beneath ........... Callichelidon} 



Genus PROG-NE, Boib. 



Procjne, BoiE, Isis, 1826, 971. (Type, Hirundo ^jw?7)(«'ea vel subis, L.) — Baird, Birds 

 N. Am. 1858, 314. 



Gen. Char. Body stout. Bill robust, lengthened ; lower or commissural edge of max- 

 illa sinuated, decidedly convex for basal half, then as concave to the tip, the lower man- 

 dible falling within its chord. Nostrils superior, broadly open, and nearly circular, without 

 any adjacent membrane, the edges rounded. Legs stout. Tarsus equal to middle toe 

 without claw ; the joint feathered ; lateral toes about equal ; the basal joint of the mid- 

 dle toe half free internally, rather less so externally. Claws strong, much curved. Nest 

 in hollow trees. Eggs white. 



The species of tliis pjenus are tlie most powerful and rohust of the Swal- 

 lows. Some are entirely glossy-black, others whitish below. The following 



1 Hirundo {Callichelidon) cyancoviridis (Bryant), Baikd, Rev. Am. Birds, 1865, 303. Baha- 

 mas. This species may yet be detected on the Florida coast. 



