. The Acarina or mites. A review of the group for the use of economic entomologists. Mites. 26 REPOKT 108, U. S. DEPARTMENT OF Fig. 24.—Cheyletus sp latt.) Superfamily TROMBIDIOIDEA. Family CHEYLETID^. The Cheyletidae are a small family of tiny mites, differing considerably in habita and structure among themselves. The typical forms are distinguished by the enor- mous palpi attached to a distinct beak. The palpi are three to five jointed, and frequently have a minute movable tubercle or papilla near the tip on inner side, which in some forms is tipped "vrith one or two pecti
. The Acarina or mites. A review of the group for the use of economic entomologists. Mites. 26 REPOKT 108, U. S. DEPARTMENT OF Fig. 24.—Cheyletus sp latt.) Superfamily TROMBIDIOIDEA. Family CHEYLETID^. The Cheyletidae are a small family of tiny mites, differing considerably in habita and structure among themselves. The typical forms are distinguished by the enor- mous palpi attached to a distinct beak. The palpi are three to five jointed, and frequently have a minute movable tubercle or papilla near the tip on inner side, which in some forms is tipped "vrith one or two pectinate bristles. This papilla is evi- dently homologous with the "thumb" of the Trombidiidae. The beak is plainly separated from the body by a deep constriction, and in front has the circular mouth opening or camerostome, through which the mandibles may be extended or re- tracted. The body is usually oval; the skin soft, occasionally with cliitinous plates, and in many forms finely striate. The division between the cephalothorax and abdomen is rarely present. The body bears a few hairs, sometimes in the form of scales. The legs are generally short, five- jointed, and usually end in two claws, with a bunch of hairs or a pectinate bristle between them. In some species the front legs terminate in bristles and appear to have a tactile func- tion; in others the front legs are transformed into clasping organs. Sometimes there is an eye on each side of the cephalothorax, but it is not often distinct. The mandibles are commonly long and needlelike, fitted for piercing tissues; in one genus, however, they have two points, indicating their chelate origin. The female genital aperture is just in front of the anus, which is at the tip of the venter. The male aperture is be- hind the anus, and often near the middle of the dorsum. The penis is very prominent, long, slender, and curved, and is often found partially extruded. The internal anatomy of the Cheyletidae has not been thorou
Size: 1212px × 2063px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherwashi, bookyear1915
