The metamorphosis of Orthocladius (Symposiocladius) holsatus Goetghebuer, 1937, with the description of Orthocladius (Symposiocladius) lunzensis sp n. (Diptera: Chironomidae)

While the holotype male of Orthocladius holsatus Goetghebuer, 1937 must be assumed lost and the original description does not allow definitive identification, a pupal exuviae at the Zoologische Staatssammlung Munchen is newly shown to constitute part of the holotype. On that basis the species was redescribed (larva, pupa, female, male) and redefined based on material reared from an egg mass collected on Lake Borken (Hesse, Germany). The investigation of the 'holsatus-material' from the Thienemann collection located at the Zoologische Staatssammlung Munchen led to the conclusion that the material from Lunzer Mittersee (Lower Austria) belongs to a new species, here described as Orthocladius lunzenis sp. n.