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Dobsonflies are a subfamily of insects, Corydalinae, part of the Megalopteran family Corydalidae. The larvae (commonly called hellgrammites) are aquatic, living in streams, and the adults are often found along streams as well. The nine genera of dobsonfllies are distributed throughout the Americas, Asia, and South Africa. ==Description== Adult dobsonflies are some of the largest non-Lepidopteran insects of temperate zones such as the United States and Canada, with a wingspan of up to 180 mm in some species of ''Corydalus''.〔 Stange, Lionel. "Alderflies and Dobsonflies." Encyclopedia of Entomology. 2nd ed. New York: Springer Publishing, 2008. 〕 A species in China has recently been reported with a wingspan of 21cm(http://www.cnn.com/2014/07/22/world/asia/giant-insect-china/). The wings vary from a grayish to translucent shade, depending on the species, and the anal region of the hindwing is wide and folded at rest. Despite the large wings, adults are weak, fluttery fliers. The body is soft and reaches up to 75 mm in length, and coloration varies from yellow to dark shades of brown.〔 Male adults are easily recognized by their long, curving mandibles, reaching up to 40 mm in length, which they use in competition for females.〔 Simonsen, T. J., Dombroskie, J. J., and D. D. Lawrie (2008). Behavioral Observations on the Dobsonfly, ''Corydalus cornutus'' (Megaloptera: Corydalidae) with Photographic Evidence of the Use of the Elongate Mandibles in the Male. American Entomologist 64 167-169. 〕 It is possible that the mandibles may have been selected as secondary sex characteristics used by females to evaluate males during courtship. Males cannot use these mandibles to bite because they are too long; on the other hand, females have short, heavily sclerotized mandibles which enable them to deliver powerful bites when threatened.〔 The antennae of males are also noticeably elongated, even longer than the mandibles. Corydalinae is distinguished from closely related clades by the following synapomorphies (with exceptions in a few species): quadrate head with a postocular spine, ridge, and plane, non-pectinate antennae, four crossveins between the radius and the radial sector, and distinctive male terminalia with a well developed ninth gonostylus.〔 In regards to the larvae, entomologist John Henry Comstock wrote in his 1897 book Insect Life,〔 Comstock, John Henry (1897). Insect Life. Cornell University Library. Online. 〕 "In spite of its disagreeable appearance it is in some respects very interesting to students of Nature study." The larvae, commonly called hellgrammites, are perhaps better known than the adults due to their more readily findable nature. They are unusual in that although they are generally aquatic, taking in dissolved oxygen through abdominal lateral filaments and tracheal gills, they also have spiracles that allow them to take in air directly when above water.〔 Contreras-Ramos, Atilano. Corydalus. Tree of Life Web Project. November 15, 1997.〕 Larvae of dobsonflies differ from those of their sister clade, the alderflies, in that they bear eight pairs of lateral processes as well as anal prolegs with a pair of terminal hooks used to hold themselves to substrate, and also in that they lack a terminal filament.〔 Borror, Donald; Triplehorn, Charles; and Norman Johnson. An Introduction to the Study of Insects. 6th ed. New York: Harcourt Brace College Publishers, 1989. 358-363. 〕 At the end of the abdomen is a pair of claw-like structures. Body color is black or dark brown. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dobsonfly」の詳細全文を読む スポンサード リンク
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