Hydrobiosella yokunna sp. nov. Figures 35–37 Holotype. Male (specimen CT-574 figured), New South Wales, Tuckers Knob, Orara West State Forest, 29°41'S, 152°48'E, 22 Nov 1990, G. Theischinger (NMV, T-20948). Diagnosis. Hydrobiosella yokunna can be separated from other species in the group by small differences in segment X and the inferior appendages; segment X in lateral view, with apex not bulbous, curved slightly downwards; lateral lobes with apical hooks directed downwards and not outwards; inferior appendages with basal segment not tapered strongly distally; harpago with ventral margin sharply angled at about 90 degrees, dilated slightly in distal half. Description. Wings similar to those of H.arcuata (fig. 1), length of forewing: male 6.9–8.5 mm. Forewing fork 2 long, length fork 2 about 1.5 times length of fork 1; length fork 3 about 1.5 times length footstalk; fork 4 length about 7.8 times length footstalk. Hind wing fork 1 with very short footstalk; fork 3 length about 1.2 times length of footstalk. Male. Sternite IX with shallow notch medially on distal margin in between a pair of small knobs (fig. 37). Tergum X mesal lobe, with a pair of short hairs/bristles subapically, in lateral view slightly downturned distally (fig. 36); in dorsal view, narrowed subapically, slightly bulbous apically (fig. 35); with a pair of pigmented lateral lobes, which terminate in small, downward projecting hooks with slightly truncate apices (figs 35–36). Inferior appendages in lateral view, with basal segment length about 1.7 times maximum width, broadest near middle, rounded distally; harpago more slender, narrowed and with ventral margin angled at about 90 degrees near middle, slightly dilated in apical third (fig. 36). Female. Unknown. Etymology. Yokunna — Australian Aboriginal word for ‘crooked’ or ‘bent’ (terminal segment of inferior appendages). Remarks. The holotype male is the only specimen of Hydrobiosella yokunna collected from the type locality in central-eastern New South Wales (latitude 29°41'S).

Published as part of Cartwright, David I., 2010, Studies of Australian Hydrobiosella Tillyard: a review of the Australian species of the Hydrobiosella bispina Kimmins group (Trichoptera: Philopotamidae), pp. 1-13 in Memoirs of Museum Victoria 67 on page 13, DOI: 10.24199/j.mmv.2010.67.01, http://zenodo.org/record/8065066