Revision of type and non-type material assigned to the genus Orthocladius by Goetghebuer (1940 - 1950), deposited in the Royal Belgian Institute of Natural Sciences (Diptera: Chironomidae) Author Magoga, Giulia ) &) &) Università degli Studi di Milano, Dipartimento di Scienze Agrarie e Ambientali (DISAA), via Celoria 2, I 20133, Milano, Italia; e-mails: giulia. magoga @ unimi. it; matteo. montagna @ unimi. it Author Montagna, Matteo ) &) &) Università degli Studi di Milano, Dipartimento di Scienze Agrarie e Ambientali (DISAA), via Celoria 2, I 20133, Milano, Italia; e-mails: giulia. magoga @ unimi. it; matteo. montagna @ unimi. it Author Marziali, Laura ) &) Water Research Institute, National Research Council (IRSA-CNR), Via del Mulino 19, I 20861 Brugherio (MB), Italy; e-mail: marziali @ irsa. cnr. it Author Rossaro, Bruno ) &) Università degli Studi di Milano, Dipartimento di Scienze per gli Alimenti, la Nutrizione e l’Ambiente (DeFENS), Via Celoria 2, I 20133 Milan, Italy; e-mail: bruno. rossaro @ unimi. it Author Disaa text Acta Entomologica Musei Nationalis Pragae 2017 Acta. Ent. Mus. Natl. Pragae 2017-12-31 57 2 723 749 http://dx.doi.org/10.1515/aemnp-2017-0097 journal article 10.1515/aemnp-2017-0097 0374-1036 5318416 638421F2-985E-43CC-8438-E871F96B1DB8 Orthocladius ( Symposiocladius ) lignicola Kieffer, 1914 Orthocladius lignicola Kieffer, 1914 in POTTHAST (1915: 273) . Material examined. 2 ♁♁ pinned, now mounted on slides, labelled: ‘ Orthocladius lignicola K. // R .I.SC.N.B. 18.073 / Coll. et det. M. Goetghebuer’, type locality not given. Comments. The differences between the species described in the subgenus Symposiocladius Cranston, 1982 ( SAETHER 2004 ) are really small and the two RBINS specimens are in poor condition, with some body parts missing. Nevertheless, the hypopygeal structure confirms that the specimens belong to Symposiocladius and the length ratio of Pm 3 / Pm 4 = 114 / 78 (about 1.5) supports the identification of O. ( S .) lignicola .