File:The descent of man, and selection in relation to sex (1874) (20841203026).jpg

Title: The descent of man, and selection in relation to sex
Identifier: descentofmansele1874darw (find matches)
Year: 1874 (1870s)
Authors: Darwin, Charles, 1809-1882
Subjects: Evolution; Natural selection; Heredity; Human beings; Sexual selection in animals; Sexual dimorphism (Animals); Sex differences
Publisher: New York : A. L. Burt
Contributing Library: Harold B. Lee Library
Digitizing Sponsor: Brigham Young University

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128 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. JSTo 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
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eig. 41. Outer tail-feather of Scolopaxgallinago (from '* 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 8, frenata (fig. 43), four feathers, and in S. javensis (fig. 43), no less than eight on each side of the tail are greatly Itg. 4a. Outer tail-feather of Scolopax frenata. Kg. 43. Outer tail-feather of Scolopax javensis. modified. Different tones are emitted by the feathers oi the different species when waved through the air; and the Scolopax Wilsonii of the United States makes a switching noise while descending rapidly to the earth.* In the male of the Cliammpetes unicolor (a large galli- I naceous bird of America), the first primary wing-feather is arched toward the tip and is much more attenuated than in *See M. Meves' 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. Blakistou, ** Ibis," vol. V, 1863, p. 131.

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