Hydromanicus canaliculatus Li, Tian, & Dudgeon 1990

Zhang, Ao & Zhou, Xin, 2021, The larvae of Chinese Hydropsychidae (Insecta: Trichoptera), Part III: Hydromanicus melli Complex, H. canaliculatus, and H. umbonatus, Zootaxa 5026 (4), pp. 527-540 : 535

Hydromanicus canaliculatus Li, Tian, & Dudgeon 1990

( Figs 3a–3d )

The larva of H. canaliculatus is overall very similar to that of H. melli Complex. Therefore, larval descriptions and illustrations presented here are primarily focused on those that can be used to differentiate the species from the H. melli Complex. The diagnosis is summarized at the end of the description.

HEAD. Head quadrate, 1.8 mm long, 1.5 mm wide ( Figs. 3a, b ). Majority of head capsule orange-brown, each eye circled by creamy yellowish round mark, posterior parietals light-colored.Anterior 1/6 of frontoclypeal apotome generally darker, flanges on middle of anterior margin of frontoclypeus being darkest. Region where frontoclypeal suture and coronal suture connected slightly dark. Tentorial pits dark, clearly visible. Muscle scars light-colored, bordered by dark pigmentation. Coronal suture curved posteriorly to left. Frontoclypeal apotome ogival, lateral sides narrowed near tentorial pits, maximum width at extreme distal end. Anterior margin of frontoclypeus asymmetrical, deeply excised, each subanterolateral corner with one large emargination, left emargination wider and deeper than right one. Anterior margin of frontoclypeus lateral to right emargination with few teeth. Medium convexity of anterior margin between two large emarginations often crenulate, with series of small flanges. Elevated ridge on left anterolateral corner of frontoclypeus and depressed regions near tentorial pits not conspicuous. Three transversely arranged brownish pits immediately posterior to dark anterior region of frontoclypeus. Two longitudinally arranged brownish pits situated mesal of each eye. Sockets of setae 17a and 17b clearly separated, with 17a situated anterolaterally to 17b. Seta 17b only slightly shorter than seta 17a. Seta 17a tapered, pale and transparent; seta 17b blunt, brownish, not transparent ( Fig. 3a , inset). Three longitudinally arranged light pits on each posterior parietal.

Stridulating files on ventral side of head rectangular, with long straight longitudinal outlines ( Fig. 3b ). Stridulating file area same color as remainder of head. Anterior ventral apotome subtriangular, with anterior margin slightly concave, generally darker than remainder of head. Posterior ventral apotome small, triangular, dark. Submentum trapezoidal, with concave anterior and convex posterior borders parallel.

THORAX. Thoracic segments overall very similar to those of H. melli . Pronotum orange brown, similar to head. Meso-, and metanota yellowish brown. All thoracic nota with glabrous appearance. Foretrochantins forked, each with dorsal branch seta-less, ventral branch with black bristles; dorsal branch shorter or as long as ventral branch, about half as wide basally as ventral branch ( Fig. 3d ). Transverse prosternal plate constricted in posterior 1/3, anterior border and middle 2/3 of posterior border black. Posterior prosternal sclerites with mesal ones uniformly light-colored, bright yellowish; anterolateral corner of each lateral sclerite darkest part of all four sclerites, remainder of lateral sclerite same color as mesal sclerites. Seta 22 on each anterolateral corner of pronotum conspicuous, long, tapered, black. Lateral region of each thoracic notum with sparsely distributed dark setae, pointing cephalad, easily identifiable from background. Number and arrangement of thoracic ventral gills same as H. melli .

ABDOMEN. Abdomen grayish brown when alive. Abdominal characteristics ( Table 2) indistinguishable from those of H. melli Complex.

Diagnosis. The larva of H. canaliculatus is very similar to those of the H. melli Complex. However, it can be differentiated from the latter based on the following diagnostic characters:

The larva of H. canaliculatus is generally smaller than those of the H. melli Complex. The head and thorax are brownish orange, making it easily differentiable from the H. melli Complex when alive as well as preserved. The abdomen of H. canaliculatus appears grayish brown when alive while that of the H. melli Complex is often greenish. The muscle scars on the head in H. canaliculatus are more conspicuous on the light background. Setae 17a and 17b do not appear to share a setal socket as in the H. melli Complex. Seta 17b is brownish and not transparent in H. canaliculatus . The dorsal branches of the foretrochantins are as long as or shorter than the ventral branches. The anterolateral corner of each lateral posterior prosternal sclerite is the darkest part of the four sclerites.

Figures

FIGURE 3. Hydromanicus canaliculatus Li, Tian, & Dudgeon 1990, larva. 3a, head, dorsal, with setae 17 further enlarged (left view, lateral, with both setae pointing anterad and 17b situated posteromesal of 17a); 3b. head, ventral; 3c, prosternal plate and posterior prosternal sclerites, ventral; 3d, left foretrochantin, left lateral.