BIRDS OF NORTH AND MIDDLE AMERICA 



67 



//. Tail less than half as long as wing; males with a conspicuous tuft 

 of elongated feathers and a large inflatable air sac on each side of 



neck Tympanuchus (p. 206) 



dd. Tail strongly graduated, with middle pair of rectrices projecting con- 

 spicuously beyond the next pair Pedioecetes (p. 1'87) 



aa. Tail nearly, to quite, as long as wing, strongly graduated, rectrices (20) nar- 

 row, acuminate, and rigid; tarsus longer than middle toe with claw; feathers 

 of chest very rigid, with spiny shafts; portion of culmen between nasal 

 fossae much longer than terminal portion ; stomach membranous. 



Centrocercus (p. 223) 



Genus DENDRAGAPUS Elliot 



Dendragapus Elliot, Proc. Acad. Nat. Sci. Philadelphia, 1864, 23. (Type, as desig- 

 nated by Baird, Brewer, and Ridgway, 1874, Tetrao obscurus Say.) 

 Dendrogapus (emendation) Giebel, Thesaurus Orn., ii, 1874, 33. 

 Tympanuchus Rjeichenow, Die Vogel, i, 1913, 320, part. 



Medium-size or rather large wood grouse (length about 432-584 mm.) 

 with tarsi feathered to or beyond base of toes ; tail more than two-thirds 

 as long as wing, rounded to truncate, of 20 rectrices; side of neck with 

 an inflatable air sac but without tufts ; the adult males with underparts 

 mostly plain grayish. 



Figure 7. — Dendragapus obscurus. 



Bill relatively small, its length from nostril about one-fourth the length 

 of head, about as deep as wide at frontal antiae ; the culmen rounded (not 

 distinctly ridged), the rhamphotheca completely smooth, the maxillary 



