. The descent of man and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings. Caxp. X.] ORTUOPTERA. 343 ; ** Dr. .^cu«l»k r w:i8 alile to excite one of lh^^e in- Hects to answer him, l>y rubbing on a tile with a le auro- duced. In the males of the Achetifliu both win«;-covers iiave the same structure; and this in the field-cricket (Grylius carnjKstris^ lig. 10) couhlsts, as descrilxd by ," of from 131 to 138 sharp, transverse ridges or teeth (at) on the under side of one of the uervures of the wing-cover. This toothed nervure is rapidl
. The descent of man and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings. Caxp. X.] ORTUOPTERA. 343 ; ** Dr. .^cu«l»k r w:i8 alile to excite one of lh^^e in- Hects to answer him, l>y rubbing on a tile with a le auro- duced. In the males of the Achetifliu both win«;-covers iiave the same structure; and this in the field-cricket (Grylius carnjKstris^ lig. 10) couhlsts, as descrilxd by ," of from 131 to 138 sharp, transverse ridges or teeth (at) on the under side of one of the uervures of the wing-cover. This toothed nervure is rapidly scrajied acrusK a projecting, smrxfth, hard nervure (r) on the U|»| surface of the opposite wing. First one wing is rublicd over the other, and then the movement is reversed, Hoth winirs are raised a little at the same time, so as to increase the resonance. In some s|K*cie« the wing-coveni of the nudim are funiished at the base with a talc-lik«* ; I have here given a dniwing ( 11) of the teeth on the under sid«' of the ,| _nwih m nervure of another s|»ecii»s of (Jry 11 us, vir. IJ In the l«4H-u^itda' flu* wing-t ' 'v, iJc in- in a .d manner, ' ». ll wiii>», h acts nM the Imiw of the fiddle, llin «i\ r . r* -hi RtTM a tvry i ntiM of the litroo Ian iIm) \\ r«|wooii pp. â Wr. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Darwin, Charles, 1809-1882. New York, D. Appleton and company
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Keywords: ., bookcentury1900, bookdecade1900, booksubj, booksubjecthumanbeings
