HIRUNDINID^. 267 



as occurring on the Pacific slope of the continent. In the fact of 

 its being a bird of the eastern province of the United States during 

 summer, and in winter crossing the mountains of nortl^ern Mexico 

 to the Pacific coast, it appears to resemble Dendroica dominica, 

 Mniotilta varia, Larus atricilla, Sterna antillarum and anglica, etc., 

 none of which are known on the California coast at any season. 



Dendroica chrysopareia. Page 183. 



Dr. Sclater has recently stated that the specimens referred to (p. 

 185) as from San Antonio, Texas, are true D. chrysopareia, and 

 thus the species is to be included in the fauna of the United States. 



Family HIRUNDINID^. 



Bill short, triangular, very broad at base (nearly as wide as long) and 

 much depressed, narrowing rapidly to a compressed, notched tip ; mouth 

 opening nearly to the eyes. Primaries nine, graduating rapidly less from the 

 exterior one ; tail feathers twelve.' Feet weak ; tarsi scutellate, shorter than 

 middle toe and claw. Number of joints in toes normal ; basal joint of middle 

 toe partially or entirely adherent to lateral toes. Wings long, falcate. Tail 

 forked. Eyes small. Plumage compact, usually lustrous. All the American 

 species with a white patch on the sides under the wing? 



The Hirundinidse form a very vt^W marked group of birds easily 

 distinguished from all others. They exhibit a close resemblance, in 

 external appearance and habits, to the Cypselidas ; from which, apart 

 from the internal structure, they are readily distinguished by the 

 possession of nine, instead of ten primaries ; twelve, instead of ten 

 tail feathers ; scutellate tarsi, toes with normal number of joints (1. 

 2. 3. and 4., respectively, exclusive of ungual phalanges), instead of 

 a different proportion ; differeutly shaped nostrils, etc. In both 

 families the wings are developed to an extraordinary degree ; the 

 outer primary nearly twice or more than twice the length of the 

 inner, and enabling its possessor to sustain flight almost indefi-. 

 nitely. The relations of the family among the Oscines appear closest 

 to the old-world Muscicapidse. 



The precise character of scutellation of tarsus is somewhat difficult 



' Of the two specimens of Atticora fasciala before me, neither has more 

 than ten tail feathers. I do not know whether this is characteristic of the 

 species or not. 



