Cicadas are large insects made conspicuous by the courtship calls of the males. They are characterized by having three joints in their tarsi, and having small antennae with conical bases and three to six segments, including a seta at the tip. The Auchenorrhyncha differ from other hemipterans by having a rostrum that arises from the posteroventral part of the head, complex sound-producing membranes, and a mechanism for linking the wings that involves a down-rolled edging on the rear of the fore wing and an upwardly protruding flap on the hindwing. Cicadas are feeble jumpers, and nymphs lack the ability to jump altogether. Another defining characteristic is the adaptations of the fore limbs of nymphs for underground life. The relict family Tettigarctidae differs from the Cicadidae in having the prothorax extending as far as the scutellum, and by lacking the tympanal apparatus.