. Cassell's natural history. Animals; Animal behavior. ISi AATiriCAL wliicli they chiefly occur are such as Ijurrovv into the grouiul, iu Britain especially the common Dung Beetles (Geotrupes) and the Humble Bees. Besides tliese well-known parasites of insects, the family includes several species wliich infest vertebrate animals, and are sometimes great plagues. One of the best kno\vn is the " Tick" {Dermanyssus avium) that infests domestic poultrj', and also makes its way into pigeon-houses, and even into the aviaries and cages in which small birds are kept. When numerous
. Cassell's natural history. Animals; Animal behavior. ISi AATiriCAL wliicli they chiefly occur are such as Ijurrovv into the grouiul, iu Britain especially the common Dung Beetles (Geotrupes) and the Humble Bees. Besides tliese well-known parasites of insects, the family includes several species wliich infest vertebrate animals, and are sometimes great plagues. One of the best kno\vn is the " Tick" {Dermanyssus avium) that infests domestic poultrj', and also makes its way into pigeon-houses, and even into the aviaries and cages in which small birds are kept. When numerous, these parasites jire often injurious and even destructive, especially when they attack small birds; and they will also transfer their operations to the bodies of human attendants on their natural victims, some- times with very disagreeable results. Several other species of £>er)iiain/.isiis and allied genera liva parasitically upon Bats, and some of these present most remarkable characters. FAMILY VI.—IXODID^, OR TICK8. In the Ixodidas we have another family of parasitic Mites, some of which are well known in Europe under the name of Ticks, although it is in warmer climates that they most abound and attain their largest size. Some of them are indeed the largest of the Acarina, reaching a length of a thii-d of an inch or more. They are more or less ovate or sometimes nearly circular in form, covered with a leathery and very extensible skin, part of which inay, however, be horny ; the palpi are small, seated on a chin-plate ; the chelicera; are retractile and generally serrated ; the eyes are sometimes present, sometimes wanting ; and the legs are similar in form, with two claws and a pad. The sucking apparatus of these parasites is composed of the maxillie and the cheliceraj. The former combine to form a sort of ring-like lower lip, from which the ligular portion extends forward as a grooved piece, the convex surface of which is furnislied with re^•ersed booklets. The
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Keywords: ., bookcentury1800, bookdecade1890, booksubjecta, booksubjectanimals
