BIRDS — TUEDIDAE SIALIA. 



221 



probability, is tbe same witb tbat considered as peculiar to North America under the name of 

 S. oenanthoides. The differences are, as far as indicated, merely those of size, the skin described 

 by Mr. Cassin being 6.50 inches long ; the wing 4.12 ; the tail 3.00 ; the tarsus 1.25. This is, 

 however, by no means an unusual discrepancy in birds of remote localities, and until better 

 characters can be assigned there would seem little propriety in making two species. 



The Saxicola oenanthe of Europe is recognized as a regular inhabitant of Greenland, and 

 those found on the main land of America in all probability reach it from that country. 



List of specimens. 



SIALIA, S w a i n s o n . 



Sialia, Swainson, Zool. Jour. Ill, Sept. 1827, 173. (S. wilsonii.) 



Ch. — Bill short, stout, broader than high at the base, then compressed ; slightly notched at tip. Rictus with short 

 bristles. Tarsi not longer than the middle toe. Claws considerably curved. Wings much longer than the tail ; the first 

 primary spurious ; not one-fourth the longest. Tail moderate ; slightly forked. 



The species of this genus are all well marked, and adult males are easily distinguishable. In 

 all, blue forms a prominent feature. 



Above uniform dark blue ; beneath brownish red. Abdomen and crissum white.... siaKs. 



General color dark blue above and below ; crissum whitish. A broad patch on the 



scapular region (on either side) and on the sides of the breast, brownish Tedi...mexicana. 



Everywhere greenish blue, becoming whitish on the abdomen and crissum arctica. 



Comparative measurements of species. 



