200 GAME BIRDS OF NORTH AMERICA. 
ter and unsavory, caused by the particular leaves on 
which the birds feed. The American species, according 
to my views, are divided into seven genera and twenty- 
five species and subspecies. 
KEY TO THE GENERA. 
A. Legs feathered wholly, or in part. 
| RUFFED GROUSE. 
a. Legs bare from the heel downward. Bonasa. 
j Page 74. 
6. Legs feathered to the toes. 
a’, Tail square at tip. 
DUSKY GROUSE, 
Dendragapus. 
Page go. 
SPRUCE GROUSE. 
Canachites. 
Page 100. 
a’. Tail feathers 20. Air sacs present. 
6’. Tail rounded of 18 rather stiff feathers. PRAIRIE HENS. 
6". Tail feathers 16. Air sacs absent. 
Tufts of lengthened feathers over air } 7ympanuchus. 
sacs. Page IIo. 
SHARP-TAILED 
GROUSE. 
Pediecetes. 
Page 123. 
COCK-OF-THE 
PLAINS. 
1 Centrecercus. 
J 
tral pair longest. No tufts over air 
c’. Tail pointed, of 18 soft feathers, cen- 
sacs. 
d'. Tail pointed, stiff, of 20 filamentous 
feathers. Breast feathers hair-like. 
Page 136. 
PTARMIGAN. 
Lagopus. 
B. Legs and toes covered with feathers. 
Page 142. 
GENUS BONASA 
(Greek Bovaca, Latin donasus, a bison. The bird’s drumming 
resembles a bison’s bellow). 
Bonasa, Steph. Gen, Zodl., vol. xi., 1819, p.298. Type 7etrao 
umbellus, Linn, 
Head crested, rudimentary air sac covered by a tuft of broad, 
soft, glossy feathers. Tail broad, long, rounded, fan-shaped. 
