Prionolabis Osten Sacken, 1860

Podenas, Sigitas, Park, Sun-Jae & Aukštikalnienė, Hye-Woo Byun and Rasa, 2022, Prionolabis crane flies (Diptera: Limoniidae) of Korea, Journal of Species Research 11 (1), pp. 29-37 : 30-31

Prionolabis Osten Sacken, 1860

Limnophila (Prionolabis) Osten Sacken 1860: 239 . - Ishida 1959: 2-3. - Alexander 1966: 379, 391.

Prionolabis Savchenko & Krivolutskaya 1976: 58 , 70. - Savchenko 1983: 50; 1986: 299; 1989: 112-113.

Type species - Limnophila rufibasis Osten Sacken, 1860 (Nearctic).

Adult.

Small to medium-sized crane flies with body length 6.0- 11.5 mm, wing length 6.9 mm to 11.5 mm in fully winged specimens, females of some species brachypterous with wing length about 3.5 mm. General body coloration varies from brownish yellow to dark brown, gray, or black, but most species are dark colored.

Head: Rounded posteriorly without neck-like exten- sion. Eyes widely separated in both sexes, width of ver- tex approximately equals length of both basal antennomeres taken together. Male antenna medium-long to long, reaching from base of wing to tip of abdomen, if bent backwards, female antenna shorter. If antenna shorter, then length of verticils approximately equals length of respective segments, but if longer, then verticils missing. Flagellomeres covered with erect pubescence on ventral side. Scape elongate, subcylindrical, pedicel short, egg-shaped. Flagellum usually 14-segmented, sometimes 13-segmented, flagellomeres short or elongate. Rostrum short.

Thorax: Frontal margin of pronotum without emar- gination. Mesonotal prescutum without tubercular pits, pseudosutural fovea closer to anterior margin of sclerite, longitudinal stripes missing. Pleuron uniformly colored, katepisternum setoseless. Meron small, thus middle and posterior coxae close together. Wing wide and pattern- less ( Fig. 1A ), wing cells without macrotrichiae. Females of many species with reduced wings unsuitable for flight ( Fig. 1B ). Arculus present. Vein Sc long, reaching wing margin at or slightly beyond branching point of Rs, sc-r before tip of Sc. Radial sector long, arched or angulate and short spurred at base, usually branching into R 2 + 3 + 4 and R 5, but in some species into R 2+ 3 and R 4 + 5. Length of R 1 varies from short and oblique to slightly elongate. R 2 before R 1 tip, but position varies according to species. R 3 and R 4 diverging. Cell r 3 with short stem, or stem is missing completely. Cell m 1 present or absent, if present, then it has long stem distinctly longer than cell itself. Discal cell slightly elongate. Cross-vein m-cu at about one-third to middle of discal cell. Vein CuP and anal vein slightly diverging. Anal vein slightly sinuous, reaching wing margin close to the level of Rs base. Anal cell long with widely rounded posterior margin. Calypter setoseless. Halter long. Legs with well developed tibial spurs, single on fore, paired on middle and posteri- or leg. Claw simple, without spines. Arolium reaching to about middle of claw or beyond that.

Abdomen: Abdominal tergites with paired transverse sutures. Male terminalia just slightly wider than the rest of the abdomen. Ninth segment fused into complete gen- ital ring. Ninth tergite emarginate or with two lobules at middle of posterior margin. Gonocoxite without inter- base. Two pairs of terminal gonostyli. Outer gonostylus usually complicated with dentate or branched apex, often with additional lobe at middle or at base. Inner gonostylus often sclerotized with dentate or branched distal part. One pair of parameres. Paramere usually flattened, sometimes narrow, rod-shaped. Aedegus elongate, narrows towards tip, apex curved downwards. Ovipositor elongate. Distal part of cercus raised upwards, blunt-apexed.

Preimaginal stages unknown.

Genus has 73 extant species and no recognized subgenera. It has Holarctic and Oriental distribution, with most species recorded from Eastern Palaearctic (33) and Nearctic (23) ( Oosterbroek, 2021). Fossils belonging to this genus unknown ( Evenhuis, 2014).

Figures

Fig. 1. Sexual dimorphism in Prionolabis Osten Sacken, 1860. A. male of P. acanthophora (Alexander, 1938). B. female of P. hospes (Egger, 1863). Scale bars: 1.0 mm.