The false scorpions, Chermetidae, may at once be recognized by their large maxillary palpi, resembling the maxillae of the true scorpion. They are small insects, rarely exceeding a quarter of an inch in length, and are found in dark shady places and feed upon mites, Psoci, and other small insects. A common species is represented at figure 132. [Illustration: FIG. 132.--False Scorpion (_Chelifer cancroides_ L.).--From Packard.] The true scorpions, Scorpionidae, are well-known forms, and are easily recognized by their large, powerful, forceps-like maxillae, and the long slender tail continuous with the thorax and ending with a sting, which is, in most cases, quite poisonous. They are found mostly in the Western and Southwestern States, and are dangerous in proportion to their size. The poisonous nature of the sting of these animals is, however, generally overrated, and the wounds, even of the larger species, are rarely fatal. The Acarina or true mites are the lowest representatives of the Arachnida and include many genera and species differing very widely in habit and characters. Some of them are mere sacs, on which the mouth parts or other organs are scarcely discernible. In general they resemble spiders. The young, however, when they leave the egg, almost invariably have but three pairs of feet, resembling in this respect the Hexapods. The fourth pair is added in the later stages. They are parasitic on insects and other animals, and some of them are vegetable feeders or live in decaying vegetable and animal matter. A very interesting group is comprised in the family Phytoptidae or gall-making mites which occur on the leaves of various trees and shrubs and produce curious galls or abnormal growths. These mites are elongate in form, have rudimentary mouth-parts and but four legs. A common form, _Phytoptus quadripes_, produces a gall on the leaves of the soft maple. The galls of all species should be collected and pinned and also preserved in alcohol, and specimens of the mites should be mounted in balsam. The members of the genus Sarcoptes are very minute and are the active source of the itch in the lower animals and man. Another common genus is Tyroglyphus, which includes the common cheese mite, _T. siro_. Other species of this genus also sometimes occur in enormous numbers in grocers' supplies. Still others are parasitic on insects, and one species, _T. phylloxerae_ Riley, is very beneficial, since, as its name indicates, it feeds on the Phylloxera of the grapevine. [Illustration: FIG. 133.--A true Scorpion (_Buthus carolinianus_).--From Packard.] The Ixodidae comprise the ticks which attach themselves to cattle, hogs, and man, and are not at all uncommon objects. These insects can be found on the animals they infest, and distinct species will be found to occur on most wild mammals. The common Cattle tick _Boophilus bovis_ Riley, is represented at Fig. 134. [Illustration: FIG. 134.--The Cattle-tick. (After Packard.)]