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genus, and is composed of many species, equally troublesome to the animals they infest ; whether it be the Acarus autuinnalis, or harvest-.dug, that intrudes itself under the skin of a human being; or the Acarus coicoptratorum, that torte meats the omxnon black beetle sometimes in such numbers as to occasion its death. Most of the insects of this genus are very minute; but some are of considerable size, particularly the Tick, which is frequently seen on dogs, and occasionally on cattle, where they adhere closely to the skin by means of a strong, broad, flat-shaped proboscis, edged with sharp prickles. Other contrivances, admirably adapted to the same purl osc, though varying according to circumstances, are bestowed upon the different species, most of which fix themselves tenaciously to the skin of some animal, and sometimes get beneath it ; as in the case of that loathsome disorder the itch, which is supposed to arise from a very minute species of mite, that breeds and multiplies in great numbers

ndcr the skin.

Two kinds annoy the black beetle: one of them, Acarus vcgetans, confines itself to the limbs or wing-shells of the beetle, to which it is fixed by a sort of long tail, resembling a foot-stalk, frm whence it has derived its name.