4 NORTH AMERICAN BIRDS. 



long and pointed, with small first primary (less than one fourth the second) ; wings con- 

 siderably longer than the tail, which is firm, nearly even, with broad feathers. Tarsi 

 variable, seldom as long as the skull, the scutellae fused into a continuous plate, only in 

 rare individual instances showing indications of the lines of separation. 



The genus Turdus is very cosmopolitan, occurring nearly throughout the 

 globe, excepting in Australia, and embraces species of highest perfection 

 as singers. In the large number of species known there are many varia- 

 tions in external form, but the transition from one to the other is so gradual 

 as to render it very difficult to separate them into different genera. The 

 sections of the group we adopt are the following : — 



Sexes similar. 



Hylocichla. Smallest species. Bill short, broad at base ; much depressed. Tarsi long and 

 slender, longer than middle toe and claw, by the additional length of the claw ; outstretched 

 legs reaching nearly to tip of tail. Body slender. Color : above olivaceous or reddish, beneath 

 whitish ; breast spotted ; throat without spots. 



Turdus. Bill stouter and higher. Tarsi stout and short, scarcely longer than middle toe and 

 claw. Body stout, generally whitish beneath and spotted. (Second quill longer than fifth ?) 



Planesticus. Similar to preceding. (Second quill shorter than fifth ?) Beneath mostly 

 uni-colored ; unstreaked excejjt the throat, which is whitish with dark streaks. 



Sexes dissimilar. 



Merula. Similar to Turdus. Male usually more or less black, especially on the head ; 

 females brownish, often with streaked throats. Bill distinctly notched. 



Hesperocichla. Similar to Turdus. Male reddish beneath, with a black collar. Bill 

 without notch. 



Subgenus HYLOCICHLA, Baird. 



Hylocichla, Baird (s. g.), Rev. Am. Birds, 1864, 12. (Type, Turdus mustclinus.) 



The essential characters of Hylocichla have already been given. The 



subgenus includes the small North 

 American species, with Turdus mus- 

 telinus, Gm., at the head as type, 

 which are closely connected on tlie 

 one side with Catharus, by their 

 lengthened tarsi, and with Turdus 

 by the shape of the wing. The 

 bills are shorter, more depressed, 

 and broader at base than in typi- 

 cal Turdus, so much so that the 

 species have frequently been de- 

 scribed under 3Iuscicapa. 



It is not at all improbable that 



naturalists may ultimately conclude to consider the group as of generic 



rank. 



In this group there appears to be five well-marked forms or "species." 



They are, mustelimis, Gm., pallasi, Caban., fuscescens, Steph., swainsoni. 



Turdus tnustelinus. 



