The cicada, also called the 17-year locust or dog-day cicada, is a large, fly-like insect found in most parts of the world. It makes a loud sound by the vibration of a pair of plates on its abdomen. Females lay eggs in tree twigs, often causing damage to the twigs. The dog-day cicada appears annually in summer. The 17-year locust, or periodical cicada, appears every 13–17 years. Cicada larvae spend up to 17 years in the ground feeding on roots and live only a week as winged adults. The adult is up to 50 mm (2 in) long.