Archive image from page 139 of The descent of man, and. The descent of man, and selection in relation to sex descentofmansele000darw Year: 1971 128 SEXUAL SELECTION: BIRDS. [Part II. With birds and many other animals it seems, from the comparison of allied species, to follow, that circular spots are often generated by the breaking up and contraction of stripes. In the Tragopan pheasant faint white lines in the female represent the beautiful white spots in the male;48 and something of the same kind may be observed A a Bl B Fig. 52.—Cyllo leda, Linn., from a drawing by Mr. Trimcn, showing th
Archive image from page 139 of The descent of man, and. The descent of man, and selection in relation to sex descentofmansele000darw Year: 1971 128 SEXUAL SELECTION: BIRDS. [Part II. With birds and many other animals it seems, from the comparison of allied species, to follow, that circular spots are often generated by the breaking up and contraction of stripes. In the Tragopan pheasant faint white lines in the female represent the beautiful white spots in the male;48 and something of the same kind may be observed A a Bl B Fig. 52.—Cyllo leda, Linn., from a drawing by Mr. Trimcn, showing the extreme range of variation in the ocelli. A. Specimen, from Mauritius, upper B. Specimen, from Java, upper surface surface of fore-wing. of hind-wing. A1. Specimen, from Natal, ditto. B1. Specimen, from Mauritius, ditto. in the two sexes of the Argus pheasant. However this may be, appearances strongly favor the belief that, on the one hand, a dark spot is often formed by the coloring matter being drawn toward a central point from a sur- rounding zone, which is thus rendered lighter. And, on the other hand, that a white spot is often formed by the color being driven away from a central point, so that it accumulates in a surrounding darker zone. In either case an ocellus is the result. The coloring matter seems to be a nearly constant quantity, but is redistributed, either 46 Jerdon, 'Birds of India,' vol. iii. p. 517.
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