Isocapnia Banks 1938

Isocapnia

DIAGNOSIS: Adults are dark brown (Fig. 48) often with golden-brown rugosites (mottled patterning) behind the eyes and on the pronotum (Fig. 50). The male epiproct is long and narrow (Fig. 51), especially in comparison to Capnia and Mesocapnia. The epiproct is often characteristically shaped at the apex, although this can only be seen at high magnifications. The male has a ventral vesicle extending from sternum 9 (Fig. 52), which is similar to the vesicle of Eucapnopsis (Fig. 45) but more darkly sclerotized in Isocapnia. The female subgenital plate often has diagnostic sclerotization patterns (Fig. 53, 58). The cerci of the nymph (Fig. 24) have long intrasegmental hairs in addition to shorter apical whorls. Later instar male nymphs have a posterior extension between the cerci encasing the developing epiproct.

DISTRIBUTION—Global: Holarctic— Regional: AOB, IDB— Aimag: AR, BU^, KhD*, KhG^, SE^, TO^, UB^, ZA.

DISCUSSION: The Isocapnia of Mongolia seem to be restricted to the Selenge (AOB) drainage (Fig. 49), with only a few specimens occurring in the eastern-most portions of the Internal Drainage basin. However, we suspect that this genus is more widespread due to the new record of I. kudia for Mongolia which demonstrates that members of this genus may be undersampled. Recently, the genus was revised by Zenger and Baumann (2004) and the Palearctic nymphs described and illustrated by Teselenko and Zhiltzova (2003).