Passerine Birds 257 



Colorado Springs July 25th, 1897, and there is an example in the Carter 

 collecfcion taken at Breckenridge, June 30th, 1882. 



ORDER PASSERES. 



This group embodies the ordinary perching birds and 

 contains over 6,000 species — as many as all the other orders 

 put together. It is by no means an easy order to diagnose 

 by external characters, but the following apply, at any 

 rate, to all North American forms : Bill of variable 

 shape and size, but never with a soft or tumid cere at 

 the base ; wing with nine or ten primaries, if the latter 

 the outer one usually very distinctly shorter than the 

 others ; secondaries always more than six ; tail of varying 

 size and shape, but always of twelve rectrices ; feet 

 with four toes, the first or hallux directed backwards, 

 not reversible, and always jointed at the same level as 

 the others ; oil-gland naked ; young hatched naked and 

 helpless. 



Key of the Families. 



A. Tarsus rounded behind ; sides and back of the tarsus covered 



with variously arranged scutes, with a " seam " along the 

 inner side. 



a. Ten primaries, the outer the longest ; hind toe longer than 



its claw, which is curved. Tyrannidae, p. 259. 



b. Only nine primaries, the outer (tenth) obsolete ; hind claw 



straight and longer than its toe. Alaudidse, p. 279. 



B. Tarsus covered postero-Iaterally with two entire longitudinal 



plates, meeting posteriorly to form a sharp ridge, 

 a. Primaries apparently only nine, the outer (tenth) rudimentary 

 or obsolete, not obvious, 

 a^ Outer primaries twice as long as the inner ones ; bill short; 

 broad, flat, notched and deeply cleft. 



Hirundinidas, p. 412. 

 b^ Outer primaries not twice the inner ones, 

 a* Bill slender and thin at base. 



a* Head crested, outer (tenth) primary present, but so 

 short as readily to escape notice. 



Bombycillidae, p. 424. 



