A cicada is an insect of the order Hemiptera, suborder Auchenorrhyncha, in the superfamily Cicadoidea, with large eyes wide apart on the head and usually transparent, well-veined wings. There are about 2,500 species of cicada around the world, and many remain unclassified. Cicadas live in temperate to tropical climates where they are among the most widely recognized of all insects, mainly due to their large size and remarkable acoustic talents. Cicadas are sometimes colloquially called 'locusts', although they are unrelated to true locusts, which are a kind of grasshopper. They are also known as 'jar flies'. Cicadas are related to leafhoppers and spittlebugs. In parts of the southern Appalachian Mountains in the United States they are known as 'dry flies' because of the dry shell they leave behind.