But few naturalists have busied themselves with the study of mites. The honored names of Hermann, Von Heyden, Duges, Dujardin and Pagenstecher, Nicolet, Koch and Robin, and the lamented Claparede of Geneva, lead the small number who have published papers in scientific journals. After these, and except an occasional note by an amateur microscopist who occasionally pauses from his "diatomaniacal" studies, and looks upon a mite simply as a "microscopic object," to be classed in his micrographic Vade Mecum with mounted specimens of sheep's wool, and the hairs of other quadrupeds, a distorted proboscis of a fly, and podura scales, we read but little of mites and their habits. But few readers of our natural history text-books learn from their pages any definite facts regarding the affinities of these humble creatures, their organization and the singular metamorphosis a few have been known to pass through. We shall only attempt in the present article to indicate a few of the typical forms of mites, and sketch, with too slight a knowledge to speak with much authority, an imperfect picture of their appearance and modes of living. Mites are lowly organized Arachnids. This order of insects is divided into the Spiders, the Scorpions, the Harvestmen and the Mites (Acarina). They have a rounded oval body, without the usual division between the head-thorax and abdomen observable in spiders, the head-thorax and abdomen being merged in a single mass. There are four pairs of legs, and the mouth parts consist, as seen in the adjoining figure of a young tick (Fig. 142, young Ixodes albipictus), of a pair of maxillae (_c_), which in the adult terminates in a two or three-jointed palpus, or feeler; a pair of mandibles (_b_), often covered with several rows of fine teeth, and ending in three or four larger hooks and a serrated labium (_a_). These parts form a beak which the mite or tick insinuates into the flesh of its host, upon the blood of which it subsists. While many of the mites are parasitic on animals, some are known to devour the eggs of insects and other mites, thrusting their beaks into the egg, and sucking the contents. We have seen a mite (Nothrus ovivorus, Fig. 143) busily engaged in destroying the eggs of a moth like that of the Canker worm, and Dr. Shimer has observed the Acarus? malus sucking the eggs of the Chinch bug. I have also observed another mite devouring the Aphides on the rose leaves in my garden, so that a few mites may be set down as beneficial to vegetation. While a few species are injurious to man, the larger part are beneficial, being either parasitic and baneful to other noxious animals, or more directly useful as scavengers, removing decaying animal and vegetable substances. [Illustration: 142, Ixodes albipictus and young.[8]]