. The descent of man : and selection in relation to sex . Evolution; Natural selection; Heredity; Human beings. 300 THE DESCENT OF MAN. segment, and are scraped by ridges on the femora.'" In certain Curculionidee and Carabidse," the parts are completely reversed in position, for the rasps are seated on the inferior surface of the elytra, near their apices, or along their outer margins, and the edges of the abdominal segments serve as the scrapers. In Pelo- bius Hermanni (one of Dytlscidse or water-beetles) a strong ridge runs parallel and near to the sutural margin of the elytra, and
. The descent of man : and selection in relation to sex . Evolution; Natural selection; Heredity; Human beings. 300 THE DESCENT OF MAN. segment, and are scraped by ridges on the femora.'" In certain Curculionidee and Carabidse," the parts are completely reversed in position, for the rasps are seated on the inferior surface of the elytra, near their apices, or along their outer margins, and the edges of the abdominal segments serve as the scrapers. In Pelo- bius Hermanni (one of Dytlscidse or water-beetles) a strong ridge runs parallel and near to the sutural margin of the elytra, and is crossed by ribs, coarse in the middle part, but becoming gradually finer at both ends, especially at the upper end; when this insect is held under water or in the air a stridulating noise is produced by the extreme horny margin of the abdomen being scraped against the rasps. In a great number of long-horned beetles (Longicornia) the organs are situated quite otherwise, the rasp being on the meso-thorax, which is rubbed against the pro-thorax; Landois counted 23S very fine ribs on the rasp f of Cerambyx heros. Many Lamellicorns have the power of stridu- lating, and the organs differ greatly in position. Some species stridulate very loudly, so that when Mr. F. Smith caught a Trox sabulosus, a gamekeeper, who stood by, thought he had caught a mouse; but I failed to discover the proper organs in this beetle. In Geotrupes and Typhceus a narrow ridge runs obliquely across (r. fig. 26) the coxa of each hind-leg (having in G. stercorarius 84 ribs), which is scraped by a specially projecting part of one of the abdominal segments. In the nearly allied Copris lunaris, an excessively narrow fine rasp runs along the sutural margin of the elytra, with another short rasp near the basal outer margin; but in some other Coprini the rasp is seated, according to Leconte,'' on the dorsal surface of the abdomen. In Oryctes it is seated on the pro-pygidium; and, according to the same entomologist
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Keywords: ., bookcentury1800, bookdecade1870, booksubjecthumanbeings, bookyear
