(Fig. 12)
Orthocladius trigonolabis Edwards, 1924: 170, syn. n.
Type material. Hypopygium of holotype ɗ, RUSSIA: West Taimyr peninsula, northern coast, Bonnevie Islands, 22 viii, 1901, A. A. Birula.
Although only the hypopygium remains, its very characteristic features leave no doubt about the synonymy. The nonhypopygial features described by Lundström are in agreement with the descriptions of O. (O.) trigonolabis by Soponis (1977: 96; from the lectotype) and Rossaro et al. (2003: 234).
It may be felt that Orthocladius nitidoscutellatus should be suppressed instead of being used as valid. However, according to the ICZN (1999) Code it does not fulfil any criteria for rejection, nor for reversal of precedence under Code Article 23.9. It also is unlikely that the nomenclature Commission would rule to invalidate the name, since the respective junior name has been used in too limited a number of papers.