366 SUNDEVALL's arrangement of HIRUNDINIDJ3 



CohorsG. CHELIDONOMORPH^. 

 Fam. HiRUNDiNiN^. 

 Genus Hirundo L. 



1. Rirundines genuince, or fiircicaudw, with the tail deeply forficate, 



and its lateral feathers linear, the bill at a minimum, the 

 nostrils valvate, placed low down, and opening laterally ; 

 the dorsal feathers white below the surface. (This group 

 comprehends the true " Barn Swallows" and their immediate 

 allies, and is subdivided according to pattern of coloration.) 



2. Hirundinesvarii formes. Bill and dorsal plumage as before. Nostrils 



low down, opening laterally; tail either forked (but with- 

 out narrowly elongate lateral feathers), or else nearly even. 

 *Valvinares; the nostrils partly closed with a soft scale, 

 t Highly-colored species with the belly white, and the lateral tail- 

 feathers acute. 

 a) b) Tarsi naked. Tachycineta Cab. 

 c) Tarsi feathered, Chclidon Boie. 

 tt Opaque grayish species. 



a) Tail emarginate, unspotted [ ; a tuft of feathers at base of 

 tarsus]. Cotyle Boie. 



b) Rectrices obtuse, spotted. Ptyonoprogve Reich. 



c) Tail rounded, unspotted (H. cincta Scop.). 



ttt Black-bellied species, with unspotted, scarcely forked tail. 

 Hypurolepais Gould. 

 ^*Jpertinare8 ; the nostrils rounded, with an imperfect scale, or none, 

 t Species black above ; tail deeply forked, with acute feathers. 



a) Dark above and below, the first primary serrate. Psalido- 

 proene Cab. 



h) Glossy blue-black above and below. Atticora Boie. 



c) Black above, white below. Pygochelidon Bd. 



tt Species dark colored ; tail little forked, with acute feathers. 



d) Uniform dark gray, the first primary serrate. Stelgidopteryx 

 Bd. 



e) With variegated dark colors, the rump rufous. Petrochelidon 

 Cab. 



f) Grayish above and below, streaked, the rump concolor. 

 Phedina Bp. 



3. Hirundinea fortirostres, with the bill comparatively stout and high, 



rather compressed from the middle, the whole gape curved ; 



nostrils rounded, not valvular, placed high, opening upward. 



o) Blue-black species with moderately forked tail. Progne Boie. 



b) Gray species, with little forked tail. I'hceoprogne Bd. 



The American forms of Hirundinidce have been closely 

 studied by Baird, who, in 1865 (Rev. AB. pp. 267 seq.), gave a 

 careful analysis of the genera and subgenera. The following 

 is his synopsis, somewhat abridged, expressing very clearly 

 the minor modifications of structure, although, as he observes, 

 the succession is not strictly natural : — 



