Hydrobiosella incisura sp. nov.

Figures 24–26

Holotype. Male (specimen CT-557 figured), Queensland, National Park (about 28°14'S, 153°09'E), 5 Jun. 1955, collector? (NMV, T-21478).

Diagnosis. Males of Hydrobiosella incisura can be separated from those of other species in the group by the laterally compressed apex on segment X with distinctive notch.

Description. Wings similar to H. letti (Fig. 17), length of forewing: male 6.5 mm.

Male. Segment IX in lateral view, length about 1.3 times width, projecting and tapered basally (Fig. 25), with a very shallow, wide concavity medially on distal margin (Fig. 26). Segment X robust in basal two-thirds, narrowed in apical third (Figs 24, 25), in dorsal view, slender in apical third (Fig. 24); in lateral view, narrowed subapically, dilated apically with distinctive notch (Fig. 25). Phallus generally tube-like; with a pair of straight, slender lateral ‘parameres’ arising from the phallus near base (Figs 24, 25). Inferior appendages in lateral view, with basal segment sub-rectangular, length about 2.1 times maximum width; harpago shorter, length about 0.7 times length basal segment, more slender, length about 2.5 times maximum width, tapered slightly distally, broadly rounded apically (Fig. 25).

Female. Unknown.

Etymology. Incisura – Latin for notch (apex of segment X).

Remarks. The single male specimen of Hydrobiosella incisura was collected from the type locality in south-eastern Queensland (latitude 28°14'S).