Octoglena claraqua, n. sp. (Polyzoniida: Hirudisomatidae), a new milliped from Idaho, USA; first record of the order from the western interior of North America

The milliped family Hirudisomatidae (Polyzoniida) comprises two genera in the Western Hemisphere and North America – Octoglena Wood, 1864, and Mexiconium Shelley, 1996 – and seven species, one being a new species from Idaho, the first hirudisomatid from the western interior, represented solely by an adult male. It is unique in its banded color pattern, recumbent gonopodal orientation in situ, upright anterior gonopod podomeres relative to the sternum, and the calyx configuration of the ultimate article. Despite these features, provisional assignment to Octoglena is warranted pending more material and review of all familial components under high magnification, preferably SEM. A full description is provided for O. claraqua, n. sp., along with a key to familial components in the Western Hemisphere, new locality records, and a distribution map.