812 



U. S. p. R, E. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



Sometimes the females have the upper parts waved transversely with hrownish yellow. 

 Generally there is no white on the wings, hut 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, compressed, 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 

 beliind. Tail feathers 18 in North American species. 



The Merginae or fishing ducks are represented in the United States hy three well estahlished 

 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 albellus 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. 



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

 vertical crest. 



Comparative measurements of species. 



