Procladius culiciformis ( Linnaeus, 1767 )

Brodin, Yngve, 2025, Procladius (Diptera, Chironomidae) of Europe and a global view, Zootaxa 5591 (1), pp. 1-127 : 51-55

Procladius culiciformis ( Linnaeus, 1767)

Tipula culiciformis Linnaeus, 1767 — Linnaeus (1767), Sweden, adult male, description.

Tanypus culiciformis ( Linnaeus, 1767) — Meigen (1818), adult male, adult female, description.

Tanypus sagittalis Kieffer, 1909 — Kieffer (1909), Germany, adult male, description.

Protenthes choreus ( Meigen, 1804) — Malloch (1915), United States, adult male, illustration.

Trichotanypus sagittalis ( Kieffer, 1909) — Kieffer (1918a), Lithuania, adult male, key, description.

Trichotanypus sagittalis ( Kieffer, 1909) — Kieffer (1924), adult male, key, description.

Trichotanypus scapularis Kieffer, 1924 — Kieffer (1924), Germany, adult male, key, description.

Procladius choreus ( Meigen, 1804) — Edwards (1929), England, adult male, description.

Procladius choreus ( Meigen, 1804) — Goetghebuer & Lenz (1936a), Goetghebuer & Lenz (1936b), Austria and England, adult male, adult female, key, description, illustration.

Procladius islandicus ( Goetghebuer, 1931) — Goetghebuer & Lenz (1936b), Iceland, adult male, illustration.

Procladius sagittalis ( Kieffer, 1909) — Goetghebuer & Lenz (1936a), Goetghebuer & Lenz (1936b), Belgium and Germany, adult male, key, description, illustration.

Procladius scapularis ( Kieffer, 1924) — Goetghebuer & Lenz (1936a), Goetghebuer & Lenz (1936b), Germany, adult male, key, description, illustration.

Procladius nipponicus Tokunaga, 1937 — Tokunaga (1937), Japan, adult male, description, illustrations.

Procladius sagittalis ( Kieffer, 1909) — Remmert (1953), Germany, adult male, description, illustration.

Procladius choreus ( Meigen, 1804) — Muragina-Koreneva (1957), Russia, adult male, adult female, pupa, larva, keys, descriptions, illustrations.

Procladius freemani Sublette, 1964 — Sublette (1964), Canada, United States, adult male in part, descriptions, illustrations.

Procladius culiciformis ( Linnaeus, 1767) — Roback (1971), England, Canada, and United States, adult male in part, description, illustrations.

Procladius freemani Sublette, 1964 — Roback (1971), Canada and United States, adult male in part, key, descriptions, illustrations.

Procladius freemani Sublette, 1964 var. cretis — Roback (1971), Canada, adult male, key, description, illustration.

Procladius freemani Sublette, 1964 var. 1–3— Roback (1980), United States and Canada, adult male in part, descriptions, illustrations.

Procladius choreus ( Meigen, 1804) — Fritz (1983), Germany, adult male, illustration.

Procladius nipponicus Tokunaga, 1937 —Sasa & Kikushi (1995), Japan, adult male, key, illustrations.

Procladius freemani Sublette, 1964 — Saether (2010), Canada, adult male, adult female, pupa, larva, keys, descriptions, illustrations.

Procladius culiciformis ( Linnaeus, 1767) — Widmann et al. (2023), Switzerland, adult female, description, photos.

Procladius crassinervis ( Zetterstedt, 1838) — Ratnasingham et al. (2024), Germany, adult males, adult females.

Procladius culiciformis ( Linnaeus, 1767) — Ratnasingham et al. (2024), Germany, France, Montenegro, Norway, Poland, Sweden and Switzerland, adult males, adult females, photos.

Procladius pectinatus ( Kieffer, 1909) — Ratnasingham et al. (2024), Finland, adult males, photos.

Procladius sagittalis ( Kieffer, 1909) — Ratnasingham et al. (2024), England, adult male.

Procladius sp. — Ratnasingham et al. (2024), Albania, Belarus, Finland, Germany, Montenegro, North Macedonia, Norway, Slovakia, Canada and United States, adult males, adult females, pupae, larvae, photos.

? Protenthes claripennis Malloch, 1915 — Frison (1927), United States, adult male, description.

? Protenthes claripennis Malloch, 1915 — Roback (1971), United States, adult male, description.

? Procladius freemani Sublette, 1964 — Roback (1980), United States, pupa in part, larva in part, key, descriptions, photos, illustrations.

? Procladius choreus ( Meigen, 1804) — Janeċek (1998), Austria, larva, description, illustration.

? Procladius islandicus ( Goetghebuer, 1931) — Langton et al. (2013), pupa, key, illustration.

Material examined (n = 95). BELGIUM, 1 adult male (as P. choreus, RBNS ), Gand , 51.05°N 3.72°E, 12 m a.s.l., +10 °C m.a.t., 19.iv.1914, leg. M. Goetghebuer ; 1 adult male (as Procladius sp. , RBNS), Heusden , 51.03°N 3.80°E, 5 m a.s.l., +11 °C m.a.t., 23.v.1943, leg. M. Goetghebuer. — CANADA, 1 adult male (as. P. freemani, CNCC ), Val Marie , 49.24°N 107.73°W, 795 m a.s.l., + 4 m .a.t., 14.vi.1956, leg. V. R. Vockeroth .— CZECHIA, 1 adult male ( NHRS), Lake Rozmberk, Stara Hlina , 49.05°N 14.79°E, 423 m a.s.l., +7 °C m.a.t., 19.vi.1991, leg. Y. Brodin ; 3 adult males ( NHRS), Cheb district, Vodni Nadrz Skalka Reservoir , 50.08°N 12.32°E, 439 m a.s.l., +7 °C m.a.t., 17.vi.1991, leg. Y. Brodin and M. Gransberg ; 1 adult male ( NHRS), Cheb district, Lake Pomezsky rybnik, 49.72°N 16.29°E, 568 m a.s.l., +7 °C m.a.t., 17.vi.1991, leg. Y. Brodin and M. Gransberg ; 1 adult male ( NHRS), Lake Blatec, Divcice , 49.11°N 14.31E °, 397 m a.s.l., +7 °C m.a.t., 19.vi.1991, leg. Y. Brodin and M. Gransberg ; 1 adult male ( NHRS), Lnare district, Vesky Ryb Reservoir , 49.44°N 13.82°E, 451 m a.s.l., +7 °C m.a.t., 18.vi.1991, leg. Y. Brodin. — FAROE ISLANDS, 1 adult male ( NHRS), Lake Mjauvotn , 62.12°N 7.00°W, 80 m a.s.l., +5 °C m.a.t., 27.vii.1980, leg. G. Brodin-Lindsten ; 4 adult males ( NHRS), Lake Eithis , 62.17°N 7.06°W, 135 m a.s.l., +5 °C m.a.t., 15.viii.2002, leg. Y. Brodin. — FINLAND, 2 adult males (as Procladius sp. , MZHF), Lake Puruvesi , 61.73°N 29.35°E, 75 m a.s.l., +3 °C m.a.t., 16.vii.1974, leg. B. Lindeberg ; 2 adult males (as P. pectinatus, ZMUO ), Hameenlinna, Lammin puhdistamo, 61.02°N 24.42°E, +5 °C m.a.t., 71 m a.s.l., 9.v.2015, leg. L. Paasivirta [ Barcode LEFIJ3930-16 and LEFIJ3931-16 ] ; 1 adult male (as Procladius sp. , ZMUO), Baltic Sea, Kolpanlahti Bay 61.61°N 21.63°E, 0 m a.s.l., +5 °C m.a.t., 4.vii.2015, leg. L. Paasivirta [ Barcode LEFIJ3596-16 ] ; 2 adult males (as P. cf. vesus ), Malax, Rönnskären Island , 63.06°N 20.83°E, +4 °C m.a.t., 5 m a.s.l., 30.vii‒5.viii.2018, leg. L. Paasivirta. — FRANCE, 1 adult male (as Procladius sp. , LHST), Lake d’Aumar , 42.84°N 00.15°E, 2 191 m a.s.l., +2 °C m.a.t., 24.viii.1964, leg. H. Laville ; 2 adult males (as Procladius sp. , LHST), Lake Mare Lac Long , 42.82°N 0.12°E, 2 094 m a.s.l., +3 °C m.a.t., 25.vii.1965, leg. H. Laville ; 1 adult male (as Procladius sp. 1 , LHST), Lake Gourg Nére Inferior , 42.87°N 0.18°E, 2 201 m a.s.l., +2 °C m.a.t., 26.vii.1966, leg. H. Laville ; 1 adult male (as Procladius sp. , LHST), Lake Vert , 42.86°N 0.19°E, 2 114 m a.s.l., +3 °C m.a.t., 27.vii.1966, leg. H. Laville ; 1 adult male (as Procladius sp. 1 , LHST), Lake Gourg Nére Moyen , 42.87°N 0.19°E, 2 211 m a.s.l., +2 °C m.a.t., 9.viii.1966, leg. H. Laville ; 1 adult male (as P. cf. scapularis, LHST ), Lake Port-Bielh , 42.87°N 0.19°E, 2 285 m a.s.l., +2 °C m.a.t., 13.viii.1968, leg. H. Laville ; 1 adult male (as Procladius sp. , LHST), River Lot, Golinhac , 44.61°N 2.60°E, 253 m a.s.l., +12 °C m.a.t., 22.vii.1977, leg. H. Laville ; 3 adult males ( NHRS), Corsica, Lake Melu , 42.21°N 9.02°E, 1 708 m a.s.l., +6 °C m.a.t., 25.viii.2015, leg. J. Moubayed-Breil ; 3 adult males ( NHRS), Corsica, Lake Calacuccia , 42.32°N 9.01°E, 774 m a.s.l., +10 °C m.a.t., 25.viii.2015, leg. J. Moubayed-Breil ; 1 adult male (as Procladius sp. , NHRS), Lake Remoray , 46.77°N 6.26°E, 849 m a.s.l., +7 °C m.a.t., iv.2019, leg. B. Tissot [ Barcoded ] .— GERMANY, 1 adult male (as Procladius sp. , MNHB), Berlin, Pichelberg , 52.51°N 13.22°E, 33 m a.s.l., +8 °C m.a.t., viii.1907, leg. B. Lichtwardt ; 1 adult male ( ZSMG), Münster, Dortmund-Ems canal, 51.95°N 7.66°E, 54 m a.s.l., +10 °C m.a.t., 1956 ; 1 adult male (as Procladius sp. , ZFMK), Winningen , in forest, 50.31°N 7.51°E, 66 m a.s.l., +10 °C m.a.t., 4.x.2012, leg. B. Rulik [ Barcode GBMWN781-15 ] ; 1 adult male (as P. choreus, ZFMK ), River Elz, Emmendingen , 48.11°N 7.85°E, 213 m a.s.l., +10 °C m.a.t., 10.ix.2018 [ Barcode GBOL-2625211] .— HUNGARY, 4 adult males ( NHRS), Derzsitavak Reservoir , 47.61°N 21.01°E, 86 m a.s.l., +12 °C m.a.t., 21.vi.1991, leg. Y. Brodin ; 1 adult male ( NHRS), Hortobagy Reservoir III, Hortobagyi-halasto , 47.65°N 21.09°E, 84 m a.s.l., +12 °C m.a.t., 21.vi.1991, leg. Y. Brodin. — ICELAND, 1 adult male, (as Procladius sp. , RBNS), Myvatn , 65.62°N 16.94°W, 276 m a.s.l., +3 °C m.a.t., 20.viii.1929 ; 2 adult males ( NHRS), Lake Masvatn , 65.62°N 17.24°W, 266 m a.s.l., +3 °C m.a.t., 12.vii.1978, leg. Y. Brodin ; 2 adult males ( NHRS), Lake Laugarvatn , 64.21°N 20.73°W, 76 m a.s.l., +8 °C m.a.t., 12.viii.2000, leg. Y. Brodin. — IRELAND, 1 adult male (as Procladius sp. , UCDZ), Lake Gougane Barra , 51.84°N 9.32°W, 165 m a.s.l., +8 °C m.a.t., 26.vii.1966, leg. D.A. Murray. — LEBANON, 2 adult males (as P. cf. choreus, NHRS ), Jib-Jennine stream, 33.54°N 35.69°E, 800 m a.s.l., +15 °C m.a.t., 10.v.1982, leg. J. Moubayed-Breil. — POLAND, 1 adult male ( NHRS), west of Dzwirzyno, Lake Resko Przymoirskie , 54.15°N 15.34°E, ‒ 2 m a.s.l., +9 °C m.a.t., 8.viii.2012, leg. J. Hellberg and Y. Brodin ; 2 adult males ( NHRS), west of Rabka, Lake Lebsko , 54.75°N 17.44°E and 54.76°N 17.47°E, ‒ 1 m a.s.l., +9 °C m.a.t., 8.viii.2012, leg. Y. Brodin and L. Brodin [ Barcode BSCHI696-17 and BSCHI597-17 ] .— ROMANIA, 1 adult male ( NMNB), Zigoneni Reservoir , 45.09°N 24.66°E, 379 m a.s.l., +9 °C m.a.t., vii.1974, leg. P.Albu ; 1 adult male ( NMNB), Lake Vidraru , 45.40°N 24.62°E, 803 m a.s.l., +7 °C m.a.t., vii.1974, leg. P. Albu. — RUSSIA, 4 adult males (as Procladius sp. ), Tsimlyansk Reservoir , 47.73°N 42.26°E, 31 m a.s.l., +9 °C m.a.t., vii.1979, leg. M.P. Miroshnichenko ; 3 adult males ( IANR), Lake Kolodenskoe , 59.01°N 37.06°E, 113 m a.s.l., +4 °C m.a.t., 27.v.1989, leg. A. Rybakova ; 1 adult male ( TUSF), Lake Ladoga, Sortavala , 61.74°N 30.77°E, 4 m a.s.l., +5 °C m.a.t., 4.viii.1991, leg. G. Söderman. — SLOVAKIA, 1 adult male (as Procladius sp. , ZSMG) Sládkovičovo kons., Lake Vincov les, 48.2°N 17.7°E, 120 m a.s.l., +11 °C m.a.t., 20.ix.1962, leg. Lastovka ; 2 adult males ( NHRS), Lake Liptovska Mara, Liptovsky Mikulas , 49.10°N 19.57°E, 555 m a.s.l., +6 °C m.a.t., 19.vi.1991, leg. Y. Brodin. — SPAIN, 1 adult male (as P. rivulorum, DEBE ), El Vellon Reservoir , 40.46°N 3.37°W, 830 m a.s.l., +13 °C m.a.t., 11.xi.1974, leg. N. Prat ; 1 adult male (as Procladius sp. , DEBE), Loriguilla Reservoir , 39.40°N 0.53°W, 322 m a.s.l., +15 °C m.a.t., 6.xii.1974, leg. N. Prat ; 1 adult male (as Procladius sp. , DEBE), Guadalajara, Buendia Reservoir , 40.24°N 2.46°E, 714 m a.s.l., +14 °C m.a.t., 9.xi.1974, leg. N. Prat. — SWEDEN, 1 adult male (as Procladius sp. , NHRS), Lake Vitalampi , 59.55°N 15.13°E, 322 m a.s.l., +5 °C m.a.t., 12.vii.1974, leg. P. Mossberg ; 4 adult males ( NHRS), Lake Vänern, Mariestadsfjärden Bay, Mariestad , 58.70°N 13.77°E, 44 m a.s.l., +6 °C m.a.t., 7‒9.v.1987, leg. Y. Brodin and K. Nielsen ; 1 adult male ( NHRS), Baltic Sea, Furusundsfjärden islands , 59.70°N 18.90°E, 1 m a.s.l., +5 °C m.a.t., 15.viii.2008, leg. C. Essenberg [ Barcode BSCHI085-11 ] ; 1 adult male ( NHRS), Baltic Sea coast, south of Obbola, Fläsebadet , 63.66°N 20.29°E, 0 m a.s.l., +3 °C m.a.t., 14.vii.2011, leg. N. Ericson [ Barcode BSCHI287-17 ] ; 1 adult male ( NHRS), Baltic Sea coast, Sillviken Bay, Sillviken , 63.76°N 20.45°E, 0 m a.s.l., +3 °C m.a.t., 27.vii.2011, leg. N. Ericson [ Barcode BSCHI360-17 ] ; 1 adult male ( NHRS), Baltic Sea, Ratakär Island , 63.99°N 20.89°E, 1 m a.s.l., +3 °C m.a.t., 3.viii.2011, leg. N. Ericson [ Barcode BSCHI433-17 ] ; 1 adult male ( NHRS), Baltic Sea coast, Pataholm , 56.92°N 16.43°E, 1 m a.s.l., +6 °C m.a.t., 2.vi.2012,leg. Y.Brodin [ Barcode BSCHI684-17 ] ; 1 adult male ( NHRS), Baltic Sea coast, Hamnefjärden Bay, Simpevarp , 57.42°N 16.67°E, 0 m a.s.l., +9 °C m.a.t., 2.vi.2012, leg. Y. Brodin [ Barcode BSCHI638-17 ] ; 1 adult male ( NHRS), Baltic Sea coast, Vallvik beach, 61.18°N 17.19°E, 0 m a.s.l., +5 °C m.a.t., 25.vii.2012, leg. Y. Brodin and G. Lindberg [ Barcode BSCHI611-17 ] ; 1 adult male ( NHRS), Baltic Sea coast, Sillvikskatan , 63.56°N 19.83°E, 0 m a.s.l., +3 °C m.a.t., 13.viii.2013, leg. Y. Brodin [ Barcode BSCHI825-17 ] ; 1 adult male ( NHRS), Eriksberg nature reserve, Bruket pond, 56.16°N 15.00°E, 5 m a.s.l., +7 °C m.a.t., 4.vi.2015, leg. J. Wolgast [ Barcoded ] .— SWITZERLAND, 4 adult males (as P. sagittalis, MCSN ), Lake Geneva, 46.2°N 6.1°E, 372 m a.s.l., +10 °C m.a.t., 20‒24.vi.1994, 20‒24.v.1995, 23‒28.vi.1995, leg. B. Lods-Crozet ; 1 adult male (as P. cf. sagittalis, MCSN ), small stream, Le Bainoz, Montet , 46.82°N 6.87°E, 505 m a.s.l., +9 °C m.a.t., 28.vi.2006, leg. P. Stucki ; 1 adult male (as P. choreus, MCSN ), small stream, Moulin Veigy, Srce , 46.14°N 6.03°E, 410 m a.s.l., +10 °C m.a.t., 22.vi.2006, leg. P. Stucki. — UNITED STATES, 1 adult male (as P. freemani, USNM ), Dayton, Lake Flathead , 47.86°N 114.25°W, 882 m a.s.l., + 5 m .a.t., 13.vii.1935, leg. Melander; 1 adult male (Holotype of P. freemani, USNM ), San Bruno , 37.61°N 112.42°W, 8 m a.s.l., + 12 m .a.t., 23.viii.1957, leg. R.P. Maynard .

Diagnostic characters. Figs. 1 , 3 , 13 , 40 , 107‒109 , key couplet 22. P. culiciformis has a medium long gonostylus process with a GspR that overlaps that of eleven other species of Procladius in Europe. Of these, P. exilis , P, saeticubitus , P. tenebricosus , P. lugubris and P. longistilus are distinctly separated from P. culiciformis by a slenderer gonostylus, reflected by the GsmR, and one or more other morphological characters in the key and the helpdesk. Also P. nudipennis and P. gemma are easily distinguished from P. culiciformis by several characters, although GspR overlaps.

P. culiciformis is sometimes difficult to distinguish from P. choreus in cases where the GspR overlaps (0.18‒ 0.25 versus 0.13‒0.20). When overlapping, the species might be separated by the mostly thicker gonostyus of P. culiciformis (GsmR 4.2‒5.2 versus 4.9‒5.6), and mostly bigger size as expressed by body length (4.4‒5.7 mm versus 2.9‒4.4 mm) and wing length (2.4‒3.5 mm versus 1.8‒2.8 mm).

The GspR of P. culiciformis entirely overlaps that of P. islandicus (0.18‒0.25 versus 0.18‒0.24). The species can be separated by the thicker gonostyus of P. culiciformis (GsmR 4.2‒5.2 versus 5.3‒6.4), the on average shorter setae of the front leg (BR 2‒4.5 versus 3‒6.5) and the on average lighter mid-section of the front leg tibia (whitish to light brown versus light brown to dark brown).

The GspR of P. culiciformis to some degree overlaps that of P. pruinosus (0.18‒0.25 versus 0.23‒0.30). When overlapping, the species can usually be separated by the thicker gonostylus of P. culiciformis (GsmR 4.2‒5.2 versus 5.2‒6.3) and an on average lighter mid-section of the front leg tibia (whitish to light brown versus light brown to dark brown).

The GspR of P. culiciformis slightly overlaps that of P. frigidus (0.18‒0.25 versus 0.25‒0.33). P. culiciformis can be distinguished from P. frigidus by the number of median anepisternum setae (0 versus 5‒26), the length of palpomere five divided with its width (9.3‒12.2 versus 8.0‒9.3) and an on average thicker gonostyus (GsmR 4.2‒5.2 versus 4.9‒5.8).

The status of P. culiciformis has been unclear ever since Linneus’ description in 1767. It has frequently been confused with P. choreus in Europe and North America. The holotype of P. freemani from the United States is in fact P. culiciformis , but at least some of the paratypes might be P. choreus . The adult female, pupal exuvia and larva of P. culiciformis have been described. Barcodes of adult males, adult females, pupae and larvae are available.

Geographical distribution and ecology. The circumpolar P. culiciformis has a more northern range than its possibly closest relative and morphologically similar P. choreus . In Europe P. culiciformis has been recorded from latitude 37°N in southern Spain to 66°N on Iceland and 68°N in northern Norway. It has been reported from 32 countries or autonomous regions in Europe. The most western outposts with findings in Europe are Portugal in the south and Iceland in the north. The southernmost records outside Europe are from 34°N in Lebanon and 35°N in Japan, and the northernmost from 62°N in northern Canada.

Sites with P. culiciformis have a range from +18 to ‒5 °C mean annual temperature, which is on average colder than that of P. choreus but about the same as that of the also morphologically similar P. pruinosus . It has a higher altitude record than that of the other two, reaching 2 210 m in the Pyrenees of southern France. Males of P. culiciformis , as the genus Procladius in general, become smaller, lighter and less hairy with increasing mean annual temperature.

P. culiciformis can be considered to be one of the most common species of Chironomidae in lakes and reservoirs in Europe, but for those with ultraoligotrophic conditions where no findings of the species are known. It is common in brackish water along the coast of the Baltic Sea and the Atlantic Ocean.

Quality assured findings of P. culiciformis are from 129 sites, mainly lakes and lake-like reservoirs. Larvae of the species have been found in vegetation near the shore and down to 20 m depth, and in the profundal from 2 m down to a depth record of 206 m in a clear lake in Switzerland.

Larvae of P.culiciformis can be common in slow-running streams and rivers, ponds and oligohaline to mesohaline water as in estuaries along the Baltic Sea, the Atlantic coast and the Black Sea. The larvae have sometimes been recorded in huge numbers from limnocrene springs. Man-made canals and ditches are other habitats inhabited by the larvae.

P. culiciformis , possibly together with P. pruinosus , seems to be the Procladius species which is best adapted to water with high humus content. Larvae inhabit polyhumic lakes, tarns and pools of bog systems where water transparency might be less than 0.2 m. Conditions in these habitats are often acidic with pH sometimes as low as around 4. In line with this, P. culiciformi s holds the acidity record for a Procladius species with pH 3.3 in a ditch close to the Baltic coast of northern Sweden.

P. culiciformis larvae are found in a wide range of trophic conditions, being common in oligotrophic to eutrophic conditions but less common in hypereutrophic conditions. Substantial decrease in numbers of P. culiciformis larvae have been noted for the profundal of reservoirs in Russia when the water changed from eutrophic to hypereutrophic accompanied by strongly deteriorated oxygen conditions.

P. culiciformis females produce jelly covered balls with several hundred eggs which are laid in shallow water. Larvae of P. culiciformis are known to be omnivorous feeding on algae such as diatoms, detritus and animals smaller than themselves such as crustaceans, oligochaete worms and insects including other chironomids. In the laboratory, larvae of P. culiciformis have been observed to attack much bigger larvae of the chironomid genus Chironomus and suck out their bodies. Larvae which feed mainly on animals are reported to develop more rapidly and become bigger as adults. Larvae of P. culiciformis can be important food items for common fish species such as rainbow trout (Oncorhynchys mykiss) and three-spined stickleback ( Gasterosteus aculeatus ). Adults can be food of songbirds such as the Eurasian reed warbler ( Acrocephalus scirpaceus ).

Adults of P. culiciformis are mostly found from mid-April to October, however until mid-December in southern Spain with up to four generations per year. A special case is emergence of adults in late February from a bay of the Baltic Sea in southern Sweden with winter water temperature +5 to +10 °C higher than the surroundings because of cooling water discharges from a nuclear power plant. Sex ratios in P. culiciformis are sometimes very unbalanced. A report from Japan noted that males made up less than 1% of about 16 700 collected specimens.

Countries or autonomous regions with records of P. culiciformis in Europe are Albania, Austria, Belarus, Belgium, Bulgaria, Croatia, Czechia, England, Estonia, Faroe Islands, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Montenegro, Netherlands, Norway, Poland, Portugal, Romania, Russia, Scotland, Slovakia, Spain, Sweden and Switzerland. P. culiciformis has also been recorded from Canada, China, Japan, Lebanon, Mongolia, Russia (Asia), the United States and Uzbekistan, possibly also India, Morocco and Tunisia.

References. Anikina 2009b; Anikina 2011; Armitage 1968; Baker & McLachlan 1979; Berczik 1966; Brodin 1980; Brodin & Hellberg 2023; Brodin et al. 2013; Coe 1950; Davies et al. 2022; Edwards 1929; Erbaeva & Safronov 2016; Essenberg 2009; Frison 1927; Fritz 1983; Gadawski 2020; Gadawski et al. 2022; Goedkoop & Johnson 1996; Goetghebuer 1922; Goetghebuer 1927; Goetghebuer & Lenz 1936a; Goetghebuer & Lenz 1936b; Hirabayashi et al. 2015; Holostenco et al. 2022; Iwakuma 1992; Jakubavičiűtë et al. 2017; Janeċek 1998; Kettani et al. 2022; Kieffer 1918a; Laville 1971; Langton et al. 2013; Lindegaard 1992; Lods-Crozet & Lachavanne 1994; Luferov 1956; Malloch 1915; Meigen 1818; Michailova 1996; Miroshnichenko 1982; Mol 1984; Mondal et al. 2021; Mossberg & Nyberg 1979; Mothes 1966; Moubayed-Breil et al. 2019; Mundie 1957; Munsterhjelm 1920; Muragina-Koreneva 1957; O´Dell 2018; Orendt 1991; Orendt 1993; Paasivirta 2012; Paasivirta 2020; Pagast 1931; Petridis & Sinis 1993; Prat 1979; Prat 1980; Prat et al. 1992; Prat & Rieradevall 1995; Ratnasingham et al. 2024; Remmert 1953; Rieradevall & Prat 1991; Rieradevall et al. 1998; Roback 1971; Roback 1980; Rydgård et al. 1985; Saether 2010; Sasa & Kikuchi 1995; Schirmer 1990; Shcherbina 1989; Shilova 1953; Sokolowa 1968a; Stasiukynas et al. 2024; Sublette 1964; Sublette 1979; Tavčar 1993; Thienemann & Zavrel 1916; Tokunaga 1937; Vesterinen et al. 2018; Vodopich & Cowell 1984; Wang & Zheng 1992; Widmann et al. 2023; Xie & Yin 1984; Zelentsov & Shilova 1994; Zschokke 1905; Zaupa et al. 2022.

Figures

FIGURE 1. Antenna of Procladius culiciformis, male from Hungary, with length of flagellomere 1‒12 and 13‒14 to calculate antenna AR indicated, cf. Table 2 H1.

FIGURE 13. Dorsal view of interior apodemes and length of axes used for calculation of the sternapodeme ratio for Procladius culiciformis, male from Sweden, cf. Table 2 G1‒G2, G5‒G8.

FIGURES 2‒3. Fig. 2: Frontal view of head of Procladius choreus, male from Lebanon, with characters useful for species identification indicated, cf.Table 2 H5‒H9, H11‒H12.Fig. 3: Left labium part of Procladius culiciformis, male from Switzerland, with longish thickened bristles indicated, cf. Table 2 H13.

FIGURES 40‒43. Male genitalia of Procladius species. 40: P. culiciformis from Sweden. 41: P. choreus from Romania. 42: P. bellus from Sweden. 43: P. nudipennis from Finland.

FIGURES 107‒109. Male genitalia left gonostylus of Procladius culiciformis. Fig. 107: Czechia. Fig. 108: Faroe Islands. Fig. 109: Hungary.