428 THE DESCENT OF MAN. 



a curved line with outspread tail and quivering pinions 

 and surprising velocity. The sound is emitted only during 

 this rapid descent. No one was able to explain the cause 

 until M. Meves observed that on each side of the tail the 

 outer feathers are peculiarly formed (fig. 41), having a 



lig. 41. Outer tail-feather of Scolopax gallinago (from ' k Proc. Zool. Soc.," 1858.) 



stiff saber-shaped shaft with the oblique barbs of unusual 

 length, the outer webs being strongly bound together. He 

 found that by blowing on these feathers, or by fastening 

 them to a long, thin stick and waving them rapidly through 

 the air, he could reproduce the drumming noise made by 

 the living bird. Both sexes are furnished with these feath- 

 ers, but they are generally larger in the male than in the 

 female and emit a deeper note. In some species, as in 

 S. frenata (fig. 42), four feathers, and in 8. javensis (fig. 

 43), no less than eight on each side of the tail are greatly 



Fig. 42. Outer tail-feather of Scolopax frenata. 



Fig. 43. Outer tail-feather of Scolopax javensis. 



modified. Different tones are emitted by the feathers of 

 the different species when waved through the air; and the 

 Scokpax Wilxoiiii of the United States makes a switching 

 noise while descending rapidly to the earth.* 



In the male of the Chamcepetcs unicolor (a large galli 

 naceous bird of America), the first primary wing-feather ^is 

 arched toward the tip and is much more attenuated than in 



*See M. Meves 1 interesting paper in " Proc. Zool. Soc.," 1858, p. 

 199. For the habits of the snipe, Macgillivray, "Hist. British 

 Birds," vol. iv, p. 371. For the American snipe, Capt. Blakistoii, 

 ibis," vol. v, 1863, p. 131. 



