126 BIRDS OF ILLINOIS. 



visitants. In the spring it was rare south of Minnesota, but 

 by the time it reached that State its numbers had been in- 

 creased by recruits from the southeast, and it became almost 



common.' 



SUBFAMILY ANATIN-ffi. THE DUCKS. 

 GENUS ANAS LINN^US. 



Anas LINN. S. N. ed. 10, i, 1758, 122; ed. 12, i, 1766, 194. Type, by elimination, A. boschas 

 LINN. 



GEN. CHAE. Hind toe without a membranous lobe, or "flap"; bill not spatulatc; tail- 

 feathers 14, narrow and pointed at the tip, but the middle pair not conspicuously elongated, 

 the graduation amounting to less than one third its total length ; culmen shorter than mid- 

 dle toe without tarsus. 



Having in the introduction to this work stated my intention 

 to follow the classification and nomenclature of the American 

 Ornithologists' Union's ''Check List of North American Birds", 

 I find myself obliged to group several very strongly marked 

 and obviously distinct generic - types under the generic name 

 Aims, these groups being admitted to merely subgeneric rank 

 in the scheme referred to. These so-called subgenera are char- 

 acterized as follows: 



A. Culmen longer than middle toe without claw. 



a. Width of upper mandible near tip more than one third the culmen, the upper and 

 lateral outlines more or less convex for the terminal half. 



1. Anas. Wing more than 8.00 inches ; scapulars and tertials in adult males broad, and 

 without light-colored median stripes. 



2. Querquedula. Wing less than 8.00 inches; scapulars and tertials in adult males lan- 

 ceolate, and marked with buffy or whitish median stripes. 



lj. Width of upper mandible near tip less than one third the length of the culmen, the 

 upper and lateral outlines straight for the terminal half. I (Wing less than 8.00 inches,) 



3. Nettion. 



B. Culmen shorter than middle toe without claw. 



4. Chaulelasmus. Distance from anterior border of nostril to tip of upper mandible 

 more than three times the distance from the same point to nearest loral feathers; 

 lamellae fine and very numerous (more than 30 visible from the outside); tail- 

 feathers 16. 



5. Mareca. Distance from anterior border of nostril to tip of upper mandible less 

 than three times the distance from the same point to nearest loral feathers; lamel- 

 la? coarser and less numerous (fewer than 15 visible from the outside) ; tail-feathers 

 11, the tail much graduated. 



For the greater convenience of the reader, keys to the species 

 a,re given under the separate subgeneric headings, which follow. 



