ABSTRACT
Diagnosis: L. 2-50 mm, but usually less than 10 mm. Soft-bodied; shape elongate, slender, slightly flattened, without scales. Pale brown, with the end of the abdomen of some species darkened. Head large; antennae longer than the head and stout, with an indefinite number of segments; eyes and ocelli absent. Mouthparts of the biting type but deeply recessed into the head. Wingless. Legs short, slender, and unmodified. The abdomen is long and slender, with a pair of prominent terminal cerci of several segments or with a pair of unsegmented forceps; abdominal segments 1 through 7 or 2 through 7 have small, paired, styletlike appendages. (See Fig. 3.1 for general body form.) Immature stages resemble adults, but they have fewer antennal segments. Their metamorphosis is gradual.
