Perlomyia kersti Sivec & Stark 2012, sp. n.

(Figs. 19-23)

Material examined. Holotype ♂, Japan, Iwate Prefecture, Hienuki River, headwater area, 22 km above Hayachine Dam, 3 May 2002, C.D. Kerst (PMSL). Paratype: 1♀, same data (PMSL).

Male. Forewing length 6 mm. General color dark brown to black. Epiproct falcate in lateral aspect, curved forward slightly, expanded at midlength and narrowly pointed at tip (Fig. 21). Tergum 9 with mesal lobe set in broad excavation (Fig. 19); small knobs absent from tergum 10 but bearing a shallow transverse groove near tip. Cerci thimble shaped in lateral aspect, but bearing a small dorsobasal knob. Paraprocts fused into a broad, thick process; apex of paraprocts truncate in lateral aspect (Fig. 21), but with a small posteroapical notch. Apex of sternum 9 curved slightly dorsad and strongly narrowed from body of sternum (Figs. 20-21). Vesicle short and broadly rounded at apex.

Female. Forewing length 7.5 mm. Posterior margin of sternum 7 enlarged, sclerotized and projecting over base of sternum 8 (Figs. 22-23). Sclerites of sternum 8 wide, but restricted to basal half of segment, and notched on meson; apically directed wing-like sclerites absent, but basally directed ones present.

Larva. Unknown.

Etymology. The patronym honors C.D. Kerst, collector of the type material.

Diagnosis. Among the Japanese Perlomyia which lack knobs on tergum 10, P. kersti is the only known species with a median lobe on tergum 9.