Plectus cirratus Bast. var. rhizophilus (de Man) .

de Man, 1884, pp. 113-114, pl. xvii, fig. 72, P. rhizophilus de Man.

Micoletzky, 1922, pp. 221-223, and pp. 224-225, P. cirr. Bast. v. rhizoph.

This variety differs h'om the species in its uniformly slender tail.

The finds of P. parietinus Bast., described b y Steiner (1916, pp. 51-53, fig. 1 a-c) h'om Novaya -Zemyla, no doubt belong to P. rhizophilus, being a more short-tailed fbrm of that variety.