. The descent of man : and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings. COLEOPTERA. 2^9 a narrow, slightly-raised surface, crossed by very fine, par- allel ribs, sometimes so fine as to cause irridescent colors, and having a very elegant appearance under the micro- scope. In some cases, as with Typhceus, minute, bristly or scale-like prominences, with which the whole surrounding surface is covered in approximately parallel lines, could be traced passing into the ribs of the rasp. The transition takes place by their be- coming confluent and straight, and a
. The descent of man : and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings. COLEOPTERA. 2^9 a narrow, slightly-raised surface, crossed by very fine, par- allel ribs, sometimes so fine as to cause irridescent colors, and having a very elegant appearance under the micro- scope. In some cases, as with Typhceus, minute, bristly or scale-like prominences, with which the whole surrounding surface is covered in approximately parallel lines, could be traced passing into the ribs of the rasp. The transition takes place by their be- coming confluent and straight, and at the same time more promi- nent and smooth. A hard ridge on an adjoining part of the body serves as the scraper for the rasp, but this scraper in some cases has been specially modified for the purpose. It is rapidly moved across the rasp, or conversely the rasp across the Fiff. 25. Necrophorus (from Landois). r. The two rasps, figure, part of the rasp highly magnified. Left-hand These organs are situated in widely different positions. In the carrion-beetles (Necrophorus) two parallel rasps (r, fig. 25) stand on the dorsal surface of the fifth abdominal segment, each rasp'* consisting of 126 to 140 fine ribs. These ribs are scraped against the posterior margins of the elytra, a small portion of which pro- jects beyond the general outline. In many Crioceridae, and in Clythra 4-punctata (one of the Chrysomelidse), and in some Tene- brionidae, &c.,''^ the rasp is seated on the dorsal apex of the abdo- men, on the pygidium or pro-pygidium, and is scraped in the same manner by the elytra. In Heterocerus, which belongs to another family, the rasps are placed on the sides of the first abdominal 7* Landois, 'Zeitschrift fur wiss. Zoolog.' B. xvii. 1867, s. 127. â ^5 I am greatly indebted to Mr. G. R. Crotch for having sent me many prepared specimens of various beetles belonging to these three families and to others, as well as for valuable information. He be- lieves that
Size: 2308px × 1083px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjecthumanbeings, bookyear
