Hexatoma Latreille, 1809

Podenas, Sigitas, Park, Sun-Jae, Byun, Hye-Woo & Podeniene, Virginija, 2022, Hexatoma crane flies (Diptera, Limoniidae) of Korea, ZooKeys 1105, pp. 165-208 : 165

Hexatoma Latreille, 1809

Hexatoma Latreille 1809: 260; Edwards 1938: 63 (in key), 64 (descriptive note), pl. 3, fig. 14; Alexander 1948: 528 (in catalogue); Ishida 1959: 2 (in key); Savchenko and Krivolutskaya 1976: 76 (note on distribution); Savchenko 1983: 67 (note on distribution); Savchenko 1986: 337-342 (redescription), figs 96, 173-179; Savchenko 1989: 118-119 (redescription), figs 58-60.

Nematocera Meigen 1818: 209, pl. 7, figs 1-4.

Anisomera Meigen 1818: 210, pl. 7, figs 5-8.

Peronecera Curtis 1836: 589, figs 2-7; Enderlein 1936: 22 (in key), fig. 41.

Trimacromera Enderlein 1936: 23 (in key), fig. 43.

Type species.

Hexatoma nigra Latreille, 1809 (southern Europe).

Description.

Medium-sized to large crane flies with body length 6.5-32.0 mm and wing length 7.5-21.0 mm. Body coloration varies from yellow or orange to brown and black, some species have very distinct coloration.

Head. Rounded posteriorly without neck-like extension. Vertex wide with distinct tubercle. Length of antenna varies from short, hardly reaching wing base, if bent backwards, to very long, when it exceeds body length up to 4 ×. Antennae sexually dimorphic. Males usually have longer antennae than females, but that is because of elongated basal segments of the male flagellum. Antenna has reduced number of segments, less than typical 14-16-segmented antenna of most short-palped crane flies, often male antenna 6- or 7-segmented, that of female 8-11-segmented. Verticils missing or indistinct, but male flagellum often with two longitudinal rows of short erect spines medially.

Thorax. Some species with very setose thorax, setae could be long, dense, and erect. Some species with more dense and longer pubescence in males than in females. Prothorax very narrow but wide. Mesonotal prescutum usually without, sometimes with, small indistinct tubercular pits, pseudosutural fovea small. Prescutum and presutural scutum with three or four longitudinal stripes. Pleuron usually without stripes, could be bare or setose, depending on species. Meron usually big, thus middle and posterior coxae widely separated. Wing long and narrow, patternless or with very distinct pattern, sometimes completely dark, even black, but often with light “window” in the middle, stigma present or missing. Macrotrichiae missing on wing cells. Arculus present, humeral vein close to arculus. Vein Sc long, reaching wing margin far beyond branching point of Rs, sc-r slightly before tip of Sc. Radial sector with two or three branches reaching wing margin. R1 short, nearly transverse, or slightly elongate, R3 and R4 diverging. Cell r3 with long stem. Cell m1 present or missing; two, three or four branches of M reaching wing margin. Discal cell present or missing. Position of cross-vein m-cu differs according to species. Vein CuP usually slightly arched at distal part, anal vein long, slightly sinuous or arched, reaching wing margin close to the level of Rs base. Anal angle distinct, widely rounded. Wing cells without macrotrichiae. Wing squama setoseless. All legs with tibial spurs, usually fore leg with single spur, middle and posterior legs with two spurs each. Claw simple or with single subbasal spine.

Abdomen. Tergites with paired transverse sutures. Male terminalia approximately as wide as the rest of the abdominal segments, slightly elongate. Epandrium (ninth tergite) wider than longer, posterior margin simple without additional structures. Each gonocoxite elongate, two pairs of terminal gonostyli, the shape of which are only slightly variable among different species. Aedeagus simple, short, and straight. Ovipositor usually with long and narrow cerci and hypovalvae, distal part of cercus slightly raised upwards, acute. Some species with shortened ovipositor bearing fleshy cerci and hypovalvae.

596 species belong to the genus Hexatoma worldwide, they are divided into six subgenera:

H. (Eriocera) Macquart, 1838 (556 extant and three fossil species),

H. (Cladolipes) Loew, 1865 (three species, one of them with two subspecies),

H. (Coreozelia) Enderlein, 1936 (one Western Palearctic species),

H. (Euhexatoma) Alexander, 1936 (one Oriental species),

H. (Hexatoma) Latreille, 1809 (23 species, one of them with two subspecies),

H. (Parahexatoma) Alexander, 1951 (12 species, Afrotropics only) ( Oosterbroek 2022).

Six fossil species are described from the Eocene, three of them in H. (Eriocera) , three not assigned to subgenera ( Evenhuis 2014).