Cicadas are a large and diverse group of insects in the family Cicadidae in the order Hemiptera. They are globally distributed, with especially high diversity in tropical regions. Most cicadas have a distinctive body form, with two pairs of wings, widely offset compound eyes on each side of the head, and three simple eyes (ocelli) on top of the head. They are generally large insects, ranging from 12 to 50 mm. At rest, the wings are held along the sides of the body, and generally extend beyond the abdomen without overlapping. Cicadas may be brightly or cryptically colored, and often have transparent wings. In many species, males produce distinctive sounds with specialized tymbal organs located on the abdomen. All cicadas are plant feeders with piercing mouthparts.