CLSM images of Potamia littoralis (A, B, C, E, G) and Australophyra rostrata (D, F, H). A anterior end of cephaloskeleton of second-instar larva with hooked appendage on ventral side of basal part of mouthhook (indicated by asterisk), left-lateral view. B intermediate sclerite and neighbouring elements of second-instar larva; dorsal view. C mouthhooks of third-instar larva, right-lateral view. D mouthhooks of third-instar larva, right-lateral view. E intermediate sclerite of third-instar larva; dorsal view. F intermediate sclerite and neighbouring elements of third-instar larva; dorsal view. G intermediate sclerite of third-instar larva; lateral view. H intermediate sclerite of third-instar larva; lateral view. — Abbreviations: acc, accessory stomal sclerite; aro, anterior rod; cut, cutaneous teeth; db, dorsal bridge; ds, dental sclerite; es, epistomal sclerite; is, intermediate sclerite; ls, labial sclerite; mh, mouthhook; ob, oral bar; pb, parastomal bar; r, rami; sub, suprabuccal teeth; vb, ventral bridge. Scale bars: 0.05 mm.