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 ( Orthocladius ) timoni Goetghebuer & Timon-David, 1939 ( Figs 37–40 ) Orthocladius ( Orthocladius ) timoni Goetghebuer & Timon-David, 1939: 69 . Type material examined. LECTOTYPE (pinned ♁, present designation) and PARALECTOTYPE (pinned ♁), both now mounted on the same slide and labelled: ‘ Orthocladius timoni n. sp. // type ♁ Goetghebuer // Env. Marseille 1938, leg. Timon David // R .I.SC.N.B. 18.073 / Coll. et det. M. Goetghebuer’.The labels “ Lectotype ”and “ Paralectotype ” are added on the slide near the respective specimens, an Indian ink line separates the two specimens . Comments. Orthocladius timoni was listed as a nomen dubium in Orthocladiinae by ASHE & O’CONNOR (2012) . The specimens are in good condition and the examination of the hypopygium allows the assignment of the species to the subgenus Orthocladius s. str. , but a separation from other species within the subgenus is not easy without associated exuviae or molecular data even if the details of the hypopygium, such as the anal point, the superior and inferior volsella and the presence of virga suggest a possible conspecificity with O. ( O. ) excavatus Brundin, 1947 ; the species can be considered tentatively valid, but for the same reasons reported for other species of the subgenus at present a formal synonymy is not recommended.