338 



NORTH AMERICAN BIRDS. 



blotches, and points of reddish-browu. These markings vary greatly in size, 

 number, and distribution. They are usually chiefly about the larger end. 

 In shajjc they are usually less elongated than those of the Barn Swallow, and 

 their markings are larger. This is not, however, iuvarialde, and the two 

 kinds are not always distinguishable. In length they vary IVom .875 of an 

 inch to .75, and their average breadth is .60. 



Genus HIRUNDO, Linn. 



nirundo, I.INN. Syst. Xat. 1, 10th ed. 1758, 191. (Type, E. rustim, Linn.) 



Under the generic head of Hirundo I propose to combine several groups 



of American Swallows 

 agreeing in moderate, 

 depressed bill, with 

 straight commissure, 

 and lateral nostrils 

 overhung by mem- 

 brane; the tarsi feath- 

 ered only at the upper 

 end, or else entirely 

 bare ; the lateral claws 

 moderate, not extend- 

 ing beyond the base 

 of the median ; the edge of the outer primary without hooks ; the tail varia- 

 ble in character, from a \'ery dee]") fork to a slight emargination only. 



Subgenera. 



Tarsi slightly feathered on inner face at upper end ; equal in length to middle toe 

 without claw. 



Tail very deeply forked Hirundo. 



Tail slightly forked or emarginate ....... Tnrhyn'iieUi. 



Tarsfi entirely naked; lengthened equal to middle toe and half its claw. 



Tail considerably forked Callichelidon} 



Hirundo horreoriim. 



Subgenus HIRUNDO, I-inn. 



Gkn. Char. Nostrils lateral. Tarsi short, not exceeding middle toe without its claw; 

 the upper joint covered with feathers, which extend a short distance along the inner face 

 of tarsus. Tail very deeply forked; the lateral feather much attenuated, twice as long as 

 the middle. Basal joint of middle toe free for terminal fourth on outside, for half on 

 inside. Nest partly of mud, and lined with feathers ; eggs spotted. 



In type, and in American species, the forehead and throat rufous; a black pectoral collar ; 

 tail-feathers with large light spots on inner webs. 



1 0. cyancoviridis, Bi;yant ; Baikd, Rev. 303 (lialiamas). 



