Perlomyia isobeae, Sivec & Stark, 2012

Sivec, Ignac & Stark, Bill P., 2012, Seven New Species Of Perlomyia (Plecoptera: Leuctridae) From Japan, Illiesia 8 (7), pp. 94-103 : 97-98

Perlomyia isobeae sp. n.

( Figs. 8-11)

Material examined. Holotype ♂, Japan, Nara Prefecture, Takami River, Aritoshi , 11 April 1995, Y. Hajashi ( PMSL) . Paratypes: 2♂, 3♀, same data ( PMSL) .

Male. Forewing length 5.5 mm. General color dark brown to black. Epiproct slightly curved in lateral aspect with apex appearing flat on dorsum and slightly expanded ( Fig. 10); dorsal aspect of tip saggitate ( Fig. 8). Tergum 9 not constricted mesally, but sclerotized area of segment narrowed near anterior margin ( Fig. 8); tergum 10 without small knobs. Cerci rounded with low dorsal lobe and small spine-like apex ( Figs. 8, 10); basal knob small, rounded and inconspicuous. Paraprocts fused into a broad, curved process. Sternum 9 projecting beyond paraprocts and curved gradually upwards in lateral aspect ( Figs. 9-10).

Female. Forewing length 6 mm. Posterior margin of sternum 7 straight and unproduced over sternum 8 ( Fig. 11). Sternum 8 with a broad mesal sclerite narrowly divided on meson and excavated on posterior margin; wing-like lateral areas of sclerite ribbon-shaped and attached to posterolateral margins of median sclerite.

Larva. Unknown.

Etymology. The matronym honors Professor Yu Isobe for her outstanding contributions to the study of Japanese Plecoptera and for her contribution of specimens to this study.

Diagnosis. This species is another of the four Japanese Perlomyia whose males lack small knobs on abdominal tergum 10 (see P. ainu above). It is distinguished from these similar species by the truncate epiproct tip in lateral aspect and by the presence of a low rounded lobe and small spine in dorsal aspect of the cerci.