Cicada, a large insect related to the aphid and treehopper. It has large eyes and two pairs of membranous wings. The adult is about 1 1/2 inches (4 cm) long. Cicadas live in the tropics and in North America and Europe.

Cicadas mate in late spring or summer. After mating, the female makes a long slit in the bark of a tree branch with her ovipositor, a sawlike organ at the tip of her abdomen. The ovipositor then releases the fertilized eggs into the slit; up to 600 eggs are laid at a time. In six or seven weeks, the eggs hatch into nymphs (wingless larvae). The nymphs drop from the branch to the ground and burrow into the soil to a depth of about 18 to 24 inches (45 to 60 cm), attaching themselves to roots of the tree. Nymphs feed on the sap from the roots and stay underground for a period of years. When they emerge, they shed their skin, becoming adults. Millions of cicadas emerge at once; as many as 40,000 may emerge from the base of a single tree. After emerging, they live four to six weeks. During this time, the males attract females by producing a loud pulsating sound with a pair of platelike membranes on their abdomen. Females may do extensive damage to young shade and fruit trees when they bore into the bark to deposit their eggs.

In the United States, the two most common species of cicada are the periodical cicada and the dogday cicada. The periodical cicada, also called the 17-year locust, is found throughout most of the eastern half of the United States. It is blackish brown with orange-tipped wings and red legs. The periodical cicada emerges from the ground in a given locality only once every 13 or 17 years. The dogday cicada, or dogday harvestfly, is found in the northeastern United States and southeastern Canada. It is black with green markings. It has a two-year cycle. Each synchronized population of cicadas is called a brood. In some localities, there are several broods of cicadas; although each brood maintains a 2-, 13-, or 17-year cycle, the insects may emerge in years other than those in which similar broods emerge because of the starting year of their cycles.

Periodical cicadas make up the genus Magicicada, dogday cicadas the genus Tibicen. Cicadas make up the family Cicadidae of the order Homoptera.