Ohap. XIII. 
VOCAL MUSIC. 
57 
male of another kind of grouse (Tetrao urophasianus), 
whilst courting the female, has his bare yellow oeso- 
phagus inflated to a prodigious size, fully half as large 
as the body ; ” and he then utters various grating, 
rig. 39. Tetrao cupido : male. (From Brehm.) 
