676 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Range. — Mountain districts of Palsearctic Region and western Amer- 

 ica (Alaska to Argentina). 



The Dippers are apparently allied to both the Thrushes and the 

 Wrens, perhaps more nearly to the latter, to which they bear a closer 

 resemblance in their abbreviated form and the character of their nest 

 and eggs, though they differ in their booted tarsi (in which they agree 

 with the Thrushes), more pointed wing, and other characters. In 

 their aquatic habits and covering of down they differ from all other 

 Passerine birds. 



They are found only in mountainous or hilljr districts, where they 

 frequent swift, rocky streams, in which they seek their food, consist- 

 ing of water insects and the spawn of fishes. They are at home in the 

 water, under which they propel themselves b}' motion of their wings; 

 in short, thej' fly through the water as readily as through the air. 

 Their nest is a domed structure, usually placed behind or near a water- 

 fall, covered with moss, and kept green by the spray which constantly 

 moistens it. 



The distribution of the famih' is peculiar. It occurs in Europe and 

 temperate Asia, through western North America, and- thence south- 

 ward through the Andes Mountains to the southern part of South 

 America. Only one genus is recognized, six species of which (nearly 

 one-half of those known) are found in America, all of them peculiar. 



Genus CINCLUS Borkhausen. 



Cinclus Borkhausen, Deutsche Fauna, i, 1797, 300. (T}'pe, C. hydropMlus Bork- 

 hausen, =<S'torm(s chiclus Linnfeus.) 



Aquatilis Montague, Orn. Diet., Suppl. Cat., 1813, 2. (Type, Cinclus aqtuUiciix 

 Bechstein. ) 



Hydrobata Vieillot, Nouv. Diet. d'Hist. Nat., i, 1816, 219. (Type, H. albicollis 

 Vieillot.) 



HydricMa Billberg, Synop. Faunte Seand., i, pt. 2, 1828, 75. (Type, Slurnus 

 dncliis Linnseus.) 



The characters of this genus are those of the Family Cinclidse, as 

 given on page 675. 



KEY TO THE AMERICAN SPECIES AND SUBSPECIES OP CINCLUS. 



a. No white on inner webs of remiges. (North American species. ) 

 b. Under parts not white, 

 c. Under parts plain slate-gray or ash gray, or with feathers narrowly niargined 

 at tips with whitish. 

 d. Head and neck distinctly brown; upper parts slate color, under parts slate- 

 gray, 

 e. Darker, with head and neck deep sepia brown. (Mountains of Mexico 



and Guatemala.) Cinclus mexicanus mexioanus, adults (p. 677) 



ee. Paler, with head and neck grayish brown. (Mountains of western 



North America, from New Mexico, Arizona, and California to Alaska. ) 



Cinclus mexicanus unioolor, adults (p. 679) 



