sometimes the entire abdomen has a not dense coating of hairs, or (in the agamic forms of the subgenus Besbicus and in still other agamic forms) the sides of all the abdominal segments are well coated with appressed hairs. Hypopygial spine of agamic forms large but not extending much further than the lateral lobes of the hypopygium; the spine distinctly broad, in some instances very broad, a broadened area usually nearer the tip than the base of the spine (in most wingless forms of the subgenus Acraspis the spine is of uniform width for its whole length); sometimes the dorsal point, sometimes the ventral point of the spine extends furthest; much of the spine punctate and hairy, the tip bearing a tuft of long, yellowish hairs; the whole spine a little smaller in short-winged forms and still smaller, narrower, and less hairy in bisexual forms. Ventral valves not prominent.
Legs long, wholly punctate and hairy; tarsal claws usually of moderate weight, heavy in the subgenera Besbicus and Philonix; usually strongly toothed, less strongly toothed in bisexual forms, in a few agamic females only weakly toothed.
Wings usually long, extending fully one-half of their length beyond the tip of the abdomen; or wings reduced to three-quarters or to half the normal length; or wings reduced still further, being in many cases mere stubs; the shortened wings with reduced venation. If long, the wings are clear or slightly tinged with yellow, set with short, dark hairs which form a short fringe about the entire margin, the fringe longest on the hind margin; veins moderately heavy to very heavy, the subcosta, radius, and basalis always the heaviest, dark brown, and more or less limitedly infuscated; the subcosta not reaching the margin, colorless at a point near the origin of the radius; the first abscissa of the radius arcuate-angulate to distinctly angulate at a little more than 90°, more or less infuscated, without a point or with a short point projecting from the apex of the angle into the radial cell; the second abscissa nearly straight or slightly curved or, usually, more curved especially toward the tip, the vein ending distinctly back of the margin of the wing, the tip in many species triangularly expanded; the radial cell moderately broad, sometimes short, sometimes long, always open; areolet always present; cubitus fine, continuous, reaching the basalis near the mid-point, slightly infuscated at the basalis; all of the cells clear, or the cubital and (less often) the discoidal and (rarely) the radial cells with irregular, dark spots or larger, more indefinite, more smoky patches.
Length 1.2 to 5.0 mm., the agamic forms averaging nearer 3.0 mm., the bisexual forms nearer 2.0 mm., the agamic insects in general moderately large and robust, the bisexual forms usually more slender but not always shorter than the corresponding agamic generations.
MALE.—Differs from the bisexual female of the same species in having the compound eyes a little larger, protruding further beyond the cheeks; the antennae almost uniformly dark or at least darker on the basal segments, with one more segment than in the female, the third segment a little longer than in the female and with a suggestion of a curve; the abdomen small, elongate triangulate, moderately long petio-