. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings -- Origin. 346 SEXUAL SELECTION. [Part In the last and third Family, namely, the Acridiidse or grasshoppers, the stridulation is produced in a very different manner, and is not so shrill, according to Dr. Scudder as in the preceding Families. The inner surface of the femur (fig. 13, r) is furnished with a longitudinal row of minute, elegant, lancet-shaped, elastic teeth, from 85 to 93 in number;37 and these are scraped across
. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings -- Origin. 346 SEXUAL SELECTION. [Part In the last and third Family, namely, the Acridiidse or grasshoppers, the stridulation is produced in a very different manner, and is not so shrill, according to Dr. Scudder as in the preceding Families. The inner surface of the femur (fig. 13, r) is furnished with a longitudinal row of minute, elegant, lancet-shaped, elastic teeth, from 85 to 93 in number;37 and these are scraped across the sharp, projecting nervures on the wing-covers, which are thus made to vibrate and resound. Harris38 says that when one of the males begins to play, he first "bends the shank of the hind-leg beneath the thigh, where it is lodged in a furrow designed to receive it, and then draws the leg briskly up and down. He does not play both fiddles together, but alternately first upon one and then on the ; Fig. 13.—Hind-leg of Stenobothrus pratorum: Tn Tv^m,. cr^pip<3 tLp h<mp r. the stridulating rid^e; lower figure, ln manv species Hie Udfee the teeth, forming the ridge, much mag- nf flip ohrlrnnp-n i«; "hol- nined(fromLandois). 0I tne a0aomen 1S UU1 lowed out into a great cavity which is believed to act as a resounding-board. In Pneumora (fig. 14), a South African genus belonging to this same family, we meet with a new and remarkable modifi- cation : in the males a small notched ridge projects ob- liquely from each side of the abdomen, against which the hind femora are As the male is furnished with the Platyphyllum eoncavum, " when captured, makes a feeble grating noise by shuffling her wing-covers ; 37 Landois, ibid. s. 113. 38 'Insects of New England,' 1842, p. 133. 39 Westwood, ' Modern Classification,' vol. i. p. Please note that these images are extracted from scanned page images that may have been digitally enhance
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectevoluti, bookyear1872
