Shobanov, Kiknadze et Butler, 1999 : 315 Chironomus (Camptochironomus) tentans Fabricius, 1805 : 38 Chironomus (Camptochironomus) tentans Malloch, 1915 : 445 The Chironomus group (Diptera: Chironomidae) in Lake Winnipeg, Canada Saether, Ole A. Zootaxa 2012 3275 1 19 8BG8R Shobanov, Kiknadze et Butler Shobanov, Kiknadze et Butler [151,773,1377,1403] Insecta Chironomidae Chironomus Animalia Diptera 7 8 Arthropoda species dilutus     Chironomus (Camptochironomus) dilutus  Shobanov, Kiknadze etButler, 1999: 315.  Chironomus (Camptochironomus) tentansauct. nec  Fabricius, 1805: 38.  ?  Chironomus (Camptochironomus) tentans var. pallidivittatus  Malloch, 1915: 445, not sensuEdwards 1929, see remarks under next species.   Material examined. CANADA, Manitoba, Winnipeg, Freshwater Institute Laboratory Culture, 2 females, 15.i. 1973, J.F. Flannagan; Saskatchewan, LeRoy, 2 females, 7.vi. 1967, A.L. Hamilton. Lake Winnipeg light traps: 3 kmoff Grand Rapids, 3 males, 13.vi. 1969; 10 kmoff (Sturgeonskin point) Long Point, 1 male, 14.vi. 1969; 3 kmoff McCreary Island, 1 male, 15.vi. 1969; Victoria Beach, 1 male, 25.vi. 1969; Grand Rapids Government Wharf, 10 males, 28.vi. 1969; 5 kmoff Selkirk (Horse) Island, 2 males, 29.vi. 1969; McBeth Harbour, 19 males, 30.vi. 1969. Normal non-parasitized males from Lake Winnipeg have a wing length of 4.07–5.16, 4.61 mm(10); an AR of 3.00–3.86, 3.55 (14); 20–38, 29 (10) sensilla chaetica on ta1 of p2; and 20–43, 25 (10) sensilla chaetica on ta1 of p3. The females have 170–220 (3) sensilla chaetica on p2, 160–250 (3) sensilla chaetica on p3. The male hypopygium and antenna are illustrated in Saether & Galloway gynandromorph, the others caused by mermithid infection ( Saether & Galloway 1980 fig. 7A, D, as  C. tentans) while the female genitalia are illustrated by Saether (1977 fig. 82A–C). Eight of 25 maleswere intersexes, one a probable gynandromorph, the others caused by mermithid infections ( Saether & Galloway 1980).   Remarks.It is now realized that Townes (1945)was correct in not recognizing  CamptochironomusMallochas a separate subgenus. Martin (2012)use the name camptochironomus-cytocomplex for species previously placed in the subgenus. According to Shobanov et al.(1999)Nearctic records of  C. tentansFabriciusbelong to  C. dilutusShobanov, Kiknadze & Butler, but see Spies & Saether (2004)and remarks under  C. pallidivittatus sensuEdwards. Accordingto Martin (2012)there are an eastern race and a western race to which the Lake Winnipeg population belong.  C. pallidivittatusis a senior synonym of  C. dilutusif reexamination of the typenot can show that there is no possibility for it to belong to another species such as the Nearctic  C. tentanspresently found only in Alaska. If such a possibility exists  C. pallidivittatuscould be declared a nomen dubium.  Shobanov et al.(1999: 317) gives the number of sensilla chaeticae as near 80. If they mean ta1 of mid and hind leg combined the number is in accordance with the present specimens.  Hein & Schmulbach (1971)found hybridization between  C. dilutus(as  tentans) and  C. pallidivittatus sensuEdwards. Hybridizationappears also to be present in the Lake Winnipeg material ( Fig. 2C, D). However, mermithid infections are common in Lake Winnipeg and although most specimens are more severely affected ( Saether & Galloway 1980) the illustrated hypopygia could also be caused by more slight changes. caused by parasitazion.   Distribution and ecology.  C. dilutusis known from lakes, ponds, puddles and brackish waters across the northern U.S.and Canada( Townes 1945: 135 as  C. tentans, Shobanov et al. 1999: 315, Martin 2012).  C. dilutusappears to occupy the same habitats as  C. tentanspreferring shallow stagnant waters where the bottom is covered by abundant organic detritus. The larvae are euryoxybiontic and thrive where organic pollution is high ( Townes 1945: 126, 136).