4 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



of them, as the Nightingale, the Song Thrush, and the Blackbird 

 (Planesticus merula) being renowned in this respect, while the 

 American Wood Thrushes (genus Hylocichla) and some of the Night- 

 ingale Thrushes (genus Catharus) and Solitaires (genus Myadestes) 

 are scarcely less remarkable for the quality of their melody. 



The Turdidse, as a group, are nearly cosmopolitan, only ])arts of 

 Polynesia being without representatives.'* They are most numer- 

 ously represented in the extensive area of the Pahearctic Region, 

 which possesses many peculiar genera; but the family is well devel- 

 oped in America, especially in the mountainous districts extending 

 from Mexico to the central Andes, the total number of species and 

 subspecies now known to occur in America being about one hundred 

 and fifty, belonging to nineteen genera. ^ 



KEY TO THE AMERICAN GENERA OP TURDID.E.C 



a. Bill relatively longer, narrower, and more couipi-essed, its width at frontal antise 

 little if any greater than its height at same point and decidedly less than length 

 of gouys; the latter nearly if not quite equal to half the distance from point ef- 

 mandible to malar apex (if less than the latter the tail even). 

 b. Wing less than five times as long as tarsus; middle toe (without claw) less than 

 three-fourths as long as tarsus. 

 c. Middle toe (without claw) not more than three-fifths as long as tarsus, or else 

 (Cichlherminia, part) tarsus nearly half as long as wing. 

 d. Bill relatively smaller and more slender, the exposed culmen not more 

 (usually much less) than half as long as tarsus; wing less than 115 mm. 

 e. Tail much longer than combined length of tarsus and middle toe (without 

 claw), the rectrices 12; wing at least two and a half times as long as 

 tarsus; outermost (tenth) primary obvious, sometimes half as long as 

 ninth (usually much less). 

 /. Exposed culmen longer than inner toe with claw: rump and l)usal por- 

 tion of tail white Saxicola (p. 8) 



ff. Exposed culmen shorter than inner toe with claw; rump not white; 

 no white on base of tail, or else {Calliope, part) a scarlet patch on 

 throat of male. 

 y. Mandible narrower basally, with gonys longer than the rami. 



h. Tail more or less rounded, with rectrices broader, tapering rather 



than widening terminally, the shafts of lateral pair parallel or 



convergent terminally in closed tail. 



i. Tarsus half as long as tail, or longer; plumage more or less varied, 



adult males having blue or scarlet on thi-oat and a whitish 



superciliary stripe, adult females with the latter jiresent but 



less developed. 



alt is possible that the New Zealand genus Turnagra does not belong here, in 

 which case that country also would be unrepresented. Some doubt also attaches to 

 the supposed Australian members of the group. 



''In Dr. R. Bowdler Sharpe's "Hand-List of Birds'*' (iv, 1903, 111-184) the total 

 number of species listed for the entire world (including subspecies, no distinction 

 being made) is very nearly six hundred, referred to seventy-five genera. It is pos- 

 sible, however, that a few of the genera may eventually be excluded from the Turdidte. 



c Several allied Paltearctic genera and one Hawaiian genus are introduced into the 

 key for the purpose of comparison with the most nearly related American forms. 



