568 The Heater-fowl Family 



Generic Types. Netta. Bill broad, widest at base, narrowing toward 

 tip, longer than tarsus. Culmen much depressed toward tip. Nail 

 large, more than one-third as wide as bill at middle. Outline of loral 

 feathering straight or slightly concave. Tail short and rounded. 

 Head of male crested. One species occurs as a straggler in North 

 America. 



Aythya. Bill similar to Netta except in one species, but sometimes 

 wider at tip than at base. Nail less than one-third as wide as bill at 

 middle. Outline of loral feathering convex. Tail short and rounded. 

 Head not crested. Five species occur in North America. 



Clangula. Bill much shorter than head, high and broad at base, 

 and tapering to tip. Nail small and narrow. Nostrils in front of the 

 middle of the bill. Tail rather long and rounded, more than twice as 

 long as tarsus. Head of adult male green with white spot in front of 

 eye. Two species found in North America. 



Charitonetta. Bill as in Clangula, but nostrils behind middle of 

 bill. Tail rather long and rounded, about twice as long as tarsus. 

 Head of adult male, purple, green, and violet, with broad white wedge 

 behind eye. One species in genus, a native of North America. 



Harelda. Bill much shorter than head and about as long as tarsus, 

 highest and widest at base, tapering to tip. Nail large and broad. 

 Nostrils high and near base of bill. Anterior outline of loral feather- 

 ing nearly a straight line. Tail pointed, the middle feathers in adult 

 male, as well as the scapulars, much elongated, the former as long as 

 wing. One species in genus, common throughout the northern 

 hemisphere. 



Histrionicus. Bill very small and short, much shorter than head 

 and shorter than tarsus, high and broad at base, tapering to tip. Nail 

 very large and broad, occupying entire end of bill. Nostrils as in 

 Harelda. Anterior outline of loral feathering convex. Tail short, 

 about half as long as wing, the scapulars elongated. A metallic 

 speculum. One species in genus found in northern North America. 



Camptolaimus. Bill nearly as long as head, very broad, width at 

 base equal to one-half the length of the culmen, widened toward tip by 

 leathery expansion on the edge of maxilla. Nostrils high in basal third 

 of bill. Lamellge of under mandible prominent. Feathers of cheeks 

 stiffened, bristle-like, with horny ends, extending in a convex line on 

 side of upper mandible. Tail short. Speculum white. One species 

 in genus, formerly in northeastern North America, now probably extinct. 



Eniconetta. Bill shorter than head, not swollen, and without pro- 

 longations on forehead, compressed, width at base much less than half 



