The cicadas () are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two families, the Tettigarctidae, with two species in Australia, and the Cicadidae, with more than 3,000 species described from around the world; many species remain undescribed. Nearly all cicada species are annual cicadas with the exception of the few North American periodical cicada species, genus Magicicada, which in a given region emerge en masse every 13 or 17 years.
Cicadas have prominent eyes set wide apart, short antennae, and membranous front wings. They have an exceptionally loud song, produced in most species by the rapid buckling and unbuckling of drum-like tymbals. The earliest known fossil Cicadomorpha appeared in the Upper Permian period; extant species occur all around the world in temperate to tropical climates. They typically live in trees, feeding on watery sap from xylem tissue, and laying their eggs in a slit in the bark. Most cicadas are cryptic. The vast majority of species are active during the day as adults, with some calling at dawn or dusk. Only a rare few species are known to be nocturnal.
One exclusively North American genus, Magicicada (the periodical cicadas), which spend most of their lives as underground nymphs, emerge in predictable intervals of 13 or 17 years, depending on the species and the location. The unusual timing and synchronization of their emergence may reduce cicada losses to predation by making them less reliable prey and by overwhelming predators with sheer numbers before significant losses occur.
The annual cicadas are species that emerge every year. Though these cicadas' life cycles can vary from one to nine or more years as underground nymphs, their emergence above ground as adults is not synchronized, so some members of each species appear every year.
Cicadas have been featured in literature since the time of Homer's Iliad and as motifs in art from the Chinese Shang dynasty. They have also been used in myth and folklore as symbols of carefree living and immortality. The cicada is also mentioned in Hesiod's Shield (ll. 393–394), in which it is said to sing when millet first ripens. Cicadas are eaten by humans in various parts of the world, including China, Myanmar, Malaysia, central Africa and parts of Mexico.
Etymology
The name is directly from the onomatopoeic Latin cicada.
thumb|Cicada is a 1939 film produced and distributed by the United States Department of Agriculture Motion Picture Service.
Taxonomy and diversity
thumb|A [[Magicicada cassinii|17-year cicada, Magicicada, Robert Evans Snodgrass, 1930]]
The superfamily Cicadoidea is a sister of the Cercopoidea (the froghoppers). Cicadas are arranged into two families: the Tettigarctidae and Cicadidae. The two extant species of the Tettigarctidae include one in southern Australia and the other in Tasmania. The family Cicadidae is subdivided into the subfamilies Cicadettinae, Cicadinae, Derotettiginae, Tibicininae (or Tettigadinae), and Tettigomyiinae, and they are found on all continents except Antarctica. Some previous works also included a family-level taxon called the Tibiceninae. The largest species is the Malaysian emperor cicada Megapomponia imperatoria; its wingspan is up to about .<!----> Cicadas are also notable for the great length of time some species take to mature.
At least 3,000 cicada species are distributed worldwide, in essentially any habitat that has deciduous trees, with the majority being in the tropics. Most genera are restricted to a single biogeographical region, and many species have a very limited range. This high degree of endemism has been used to study the biogeography of complex island groups such as in Indonesia and Asia. There are several hundred described species in Australia and New Zealand, around 150 in South Africa, over 170 in America north of Mexico, at least 800 in Latin America, and over 200 in Southeast Asia and the Western Pacific.
About 100 species occur in the Palaearctic. A few species are found in southern Europe, Many species await formal description and many well-known species are yet to be studied carefully using modern acoustic analysis tools that allow their songs to be characterized.