812 



U. S. p. B. E. EXP. AND SUEVETS — ZOOLOGY — GENEEAL EEPOET. 



Sometimes tlie females have the upper parts waved transversely witli brownish yellow. 

 Generally there is no white on the wings, but in one specimen from San Pasqual the secondaries 

 and the greater tail coverts are narrowly tipped with white. 



List of specimens. 



Sub-Family MERGINAE. 



Ch. — Bill very slender, narrow, compresBsd, terminated by a conspicuous nail. Edges much serrated, the serrations 

 projecting. Tarsi much compressed ; the scales anteriorly large and transverse, becoming smaller and smaller on the sides and 

 behind. Tail feathers 18 in North American species. 



The Merginae or fishing ducks are represented in the United States by three well established 

 species, placed by modern systematists in as many genera. Two of these, however, are so 

 nearly alike that I prefer to consider them as the same ; the third is sufficiently distinct. The 

 Mergus alhellus of Europe is scarcely entitled to a place in our fauna. 



The genera adopted may easily be recognized by the following characters : 



Mergus. — Most of bill red. Serrations acute, recurved. Tarsi two-thirds the length of 

 middle toe. Head with a depressed crest. 



LoPHODYTBS. — Bill black. Serrations oblique. Tarsi half the middle toe. Head with an erect 

 vertical crest. 



Comparative measurements of species. 



