Heredity and sex . Fig. 16. — Male and female mallard duck. (From Bird Lore.) 30 HEREDITY AND SEX and remain there without glowing. A male passes byand flashes his light; the female flashes back. In-stantly he turns in his course to the spot whence thesignal came and alights. He signals again. She re-plies. He ascends the blade, and if he cannot find her,he signals again and she responds. The signals con-. Fig. 17. — Male and female Herculesbeetle. (After Kingsley.) tinue until the female is found, and the drama of sexis finished. Mast has recently shown that the female firefly doesmore than s
Heredity and sex . Fig. 16. — Male and female mallard duck. (From Bird Lore.) 30 HEREDITY AND SEX and remain there without glowing. A male passes byand flashes his light; the female flashes back. In-stantly he turns in his course to the spot whence thesignal came and alights. He signals again. She re-plies. He ascends the blade, and if he cannot find her,he signals again and she responds. The signals con-. Fig. 17. — Male and female Herculesbeetle. (After Kingsley.) tinue until the female is found, and the drama of sexis finished. Mast has recently shown that the female firefly doesmore than simply respond to the signal of the a male flies above and to the right of the female, shebends her abdomen so that its ventral surface is turnedupward and to the right. If the male is above and tothe left, the light is turned in this direction. If the male THE EVOLUTION OF SEX 31 is directly above, the abdomen of the female is twistedalmost upward. But if the male is below her, she emitsher light without turning the body. In the firefly theevidence that the phosphorescent organ is of use inbringing the sexes together seems well established.
Size: 1392px × 1796px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookdecade1910, booksubjectsex, bookyear1913
