(Fig. 13)
Orthocladius binotatus Lundström, 1915: 12.? Chaetocladius validus Brundin, 1956: 126.
Type material. Hypopygium of holotype ɗ, RUSSIA: New Siberian Islands, upper reaches of Wosnessenje River, 4 vii 1903, A. W. Koltschak & P. W. Olenin.
MALE IMAGO (n = 1)
Hypopygium (Fig. 13). Anal point 94 m long, 19 m wide at apex, 30 m wide near base, free of microtrichia in apical half. Tergite IX with about 25 setae, including 5 on anal point; laterosternite IX with about 7 setae. Phallapodeme 165 m long, transverse sternapodeme 158 m long. Virga 94 m long, consisting of a cluster of about 7 spines. Gonocoxite 323 m long, gonostylus 143 m long, megaseta 19 m long. HR 2.26.
Remarks
Although only the hypopygium remains, its characteristic, uniquely long virga and the fact that Brundin placed the species in Chaetocladius should make the species easily identifiable. Unfortunately, the types of Chaetocladius validus could not be located. Although Chaetocladius is an entirely unrevised genus with a considerable number of species currently considered as valid, most of these species have been examined previously by the author in connection with a planned revision. No other species with a similar hypopygium has been observed.