Bioacoustics of Smicridea (Rhyacophylax) appendiculata

Male genitalia. Differing from specimens of original description in more-bulbous apex of phallus ( Fig. 57 ) and narrower tergum X. Pupa. Length 4–5 mm (n = 5) ( Figs 58–61 ), thorax and abdomen with sparse setae. Pupal head: Labrum with of the central lobe with 5 long setae; lateral lobes smaller, twice as long as wide, with 5 medium setae in dorsal view ( Fig. 59 ); mandibles asymmetrical and broad basally, right mandible with 5 teeth and left mandible with 4, each with brush of long basolateral setae ( Fig. 59 ). Pupal thorax. With sparse setae. Pupal abdomen. With sparse setae. In dorsal view, with pairs of hook plates anteriorly on segments II–VIII, posteriorly on segments III–IV; in hook-plate pair 2a each plate with 5 strong, straight hooks; in hook-plate pair 3a each plate with 6 strong hook plates and 10 small ones; in hook-plate pair 3p each plate with 8 strong hook plates; in hook-plate pair 4a each plate with 3 strong hook plates and 9 small ones, in hook-plate pair 4p each plate with 4 strong, upturned hooks; in hook-plate pair 5a each plate with 2 strong hooks and 8 small ones; in hook-plate pair 6a each plate with 3 strong hooks and 5 small ones; in hook-plate pair 7a each plate with 1 strong hook and 6 small ones; in hook-plate pair 8a each plate with 2 strong hooks and 3 small ones ( Fig. 61 ). Abdominal apical processes of segments IX–X straight, widely separated, each with apical brush of setae (8 short and 12 long setae) ( Fig. 60 ). Larva ( Figs 52–69 ). Length 6.5–7.5 mm (n = 8). Color in alcohol yellow-brown, lateral habitus as in Figure 62 ; body covered with short, spatulated setae. Larval head. Yellow-brown, almost square, slightly wider than long; anterior margin of frontoclypeus dark, convex, with lateral lobes protruding. In dorsal view, transverse brown band anteriorly, extending laterally; short thin setae sparsely covering dorsal and lateral regions except frontoclypeus; pairs of setae on dorsal and lateral regions of eye; short coronal suture; small dark spots on muscle insertions in posterior region; frontoclypeal suture V-shaped except with constriction at anterior tentorial pits; brown, rugose cuticle anterior of this constriction; anterior margin of frontoclypeus concave, nude and dark brown ( Fig. 63 ); 1 pair of long setae over eye (pair #9); 2 pairs of long setae, 1 on clypeus margin (pair #1) and other on lateral margins of eyes (pair #14), coronal suture short, 1 pair of median setae near clypeus anterior margin (pair #3); mandibles strong and asymmetric, left mandible with 5 mesal teeth, 1 apical tooth and 1 brush of submarginal setae at mid length; right mandible with 6 mesal teeth and 1 apical tooth, no submarginal setae ( Fig. 67 ), each mandible with rounded laterodorsal projection with 4–5 thin, dorsal setae ( Figs 63−65 ). Labrum oval, with short thin setae on most of dorsal surface, fringe of short, very thin setae on anteromesal margin, pair of long, submarginal, anterolateral setae, pair of brushes of setae on lateral areas directed anterad ( Fig. 68 ). Ventral region of each gena with stridulation file long, ranging from anterior to posterior margins of gena, coarse and well marked, but narrow. Ventral apotome divided, anterior region wider than long, triangular, sclerotized at anterior margin ( Fig. 64 ). Larval thorax. In dorsal view, sclerites brown, pronotum darker than meso- and metanota, with anterior region of each sclerite with short thin setae; pronotum with longitudinal ecdysial line, mesonotum and metanotum without longitudinal ecdysial lines ( Fig. 66 ); in ventral view, gills absent on prosternum, mesosternum with 1 pair of ventrolateral gills and metasternum with 1 pair of ventrolateral gills and 1 simple ventromesal gill, each with long stalk and few lateral filaments irregularly distributed. Legs similar, although prothoracic legs somewhat shorter than meso- and metathoracic legs; foretrochantins simple. Larval abdomen. Two pairs of ventrolateral, simple gills, on segments I–VI and VIII, 1 pair of simple and 1 pair of double gills ventrally on segments II–VII; sternum VIII with 2 small plates each having 5 medium setae along its posterior margin ( Fig. 69 ).

Diagnosis. The pupa of S. appendiculata differs from those of the other species by having the labrum with lateral lobes smaller than the central lobe; and central lobe with 5 medium setae on each of the lateral lobes and 5 long setae on the central lobe, in pupa of S. helenae sp. nov. has 4 long setae on each of the lateral lobes and 5 medium setae on the central lobe, while S. dithyra has 4 long setae on each lateral lobe and 9 long setae on the central lobe. The pupa of S. appendiculata also differs from those of the other species by having hook plates on segments as described below and by differences in the form and number of hooks, in S. appendiculata in hook-plate pair 2a each plate has 5 strong, straight hooks; in hook-plate pair 3a each plate has 6 strong and 10 small hooks, in hook plates 3p each plate has 8 strong hooks; in hook plates 4a each plate has 3 strong and 9 small hooks, in hook plates 4p each plate has 4 strong hooks; in hook plates 5a each plate has 2 strong hooks and 8 small hooks; in hook plates 6a each plate has 3 strong hooks and 5 small hooks; in hook plates 7a each plate has 1 strong hook and 6 small hooks; in hook plates 8a each plate has 2 strong hooks and 3 small hooks. The larva of S. appendiculata can be distinguished from those of other species in the subgenus by its V-shaped frontoclypeal suture with a constriction at the anterior tentorial pits; by the anteior margin of the frontoclypeus being concave, nude and dark brown; by the laterodorsal projections on the mandibles; and by the long stridulation file, ranging from the anterior to the posterior margin, coarse and well marked, but narrow.