are insects in the grasshopper group Most katydids have large green leaf like wings and long antennae. They have the loudest calls of all the grasshoppers. They use one forewing as a fiddle and the other as a bow to produce a sound that attracts mates and warns other katydids. Many katydids seem to call, Katydid, katydidn't." They make this call only in the evenings and at night. Katydids are common in North America. They are eaten by many birds. In the autumn, katydids lay eggs on twigs and leaves or the ground. In spring, young katydids hatch. See also grasshopper,