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 Hydrobaenus conformis (Holmgren, 1869) Chironomus conformis Holmgren, 1869: 42 . Orthocladius obesus Goetghebuer, 1940: 60 . Type material examined. Orthocladius obesus : HOLOTYPE : pinned , now mounted on slide, labelled: ‘ Orthocladius obesus n. sp. // type / M. Goetghebuer // type locality Abisko Lapp Sved Thienemann 1939 // R .I.SC.N.B. 18.073 / Coll. et det. M. Goetghebuer’ . Figs 7‒12. Georthocladius scaturiginis ( Goetghebuer, 1940 ) . 7 ‒ claws and pulvilli, 8 ‒ thorax, 9 ‒ wing points, 10 ‒ anal point, 11 ‒ inferior volsella, 12 ‒ gonostylus. Comments. The synonymy of O. obesus with H. conformis was already proposed by SAETHER (1976) , even if the type material was probably not examined; the present examination of the holotype confirms the synonym.