Mite, a name applied to many very small articulated animals, of the arachnoid order and suborder acarina, including the ticks, itch insects, and other parasites, and the minute acari. The abdomen is unarticulated, and fused with the cephalothorax; the external envelope is of chitine, solid and indestructible; four pairs of feet on the cephalothorax, armed with nails, and in some provided with long pedunculated disks by which the animal is attached; some, when young, have six feet; eyes usually absent; mandibles wanting, the antenna) being changed into prehensile and masticatory organs, moving vertically, piercing or cutting as may be necessary, and sometimes enclosed in a sheath in the form of a sucker. The stomach has several caecal appendages, and the short and straight intestine opens near the middle of the abdomen; salivary glands well developed; no apparent heart nor blood vessels, the colorless nutritive fluid filling all the interstices of the body, and being irregularly circulated by the muscular movements and the contractions of the intestinal canal; respiration aerial, performed chiefly by the skin, and in some by trachese.

The sexes are separate; many have an ovipositor, by which they insert their eggs under the epidermis of plants and animals, in the latter case often causing great irritation; some surround their eggs by a tough substance which glues them to various objects. • Their extreme minuteness in some cases may be judged of by the fact that they infest flies and very small insects; they are exceedingly prolific. Some live under stones, others on plants, on animals, or among decaying organic substances, and a few are aquatic; the parasitic ones, sucking the blood of animals and man, are sometimes very annoying. The itch insect has been described under Itch, and the ticks and other mites under Epizoa. Among the mites, the acarus domes-ticus is found especially in old cheese (the powder of which, so agreeable to epicures, is made up of these little animals with their eggs and excrement), in flour, sugar, and on figs and sugared fruits; the A. destructor feeds on the specimens of the entomologist and zoologist; the garden mites(trom-didiidce) live on fruits, flowers, and leaves; the spider mites (gamasidae) include the minute red spider of hothouses; and the wood mites (orvbatidce) creep among stones and moss.