Very small, less than 0.39 in (10 mm) in length, but usually averages only 0.12 in (3.0 mm) in length. Does not have eyes. Has divided prosoma covered anteriorly by propeltidium and by two free tergites: the mesopeltidium and metapeltidium. One-third to one-tenth its greatest dimension separates large mesopeltidia. Short abdominal flagellum is located on last ab dominal segment. Flagellum is segmented in females. Abdomen has eight pairs of dorsoventral muscles, which are not flattened. Chelicerae lack a serrula, but have two blunt hemispherical knobs. Has fixed digit with two teeth, and no setae at base. Basitarsal spurs are symmetrically located, about one-third to one-half dorsal length of basitarsus. Feeler-like first legs are used for sensory purposes. Lacks patellae. Tarsi have eight pieces and no claws. Trochanter of fourth leg is about 2.2 times longer than wide; fourth femur is 3-5 times longer than wide. Anal glands are present. One pair of book lungs.
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