Description of the final instar larva of Helicopsyche revelieri

Biometry. Body length from 4.5 to 5.1 mm, head width from 0.50 to 0.61 mm (n = 4). All morphological characters identical to those of H. megalochari except as noted below.

Head. Upper surface of head capsule reddish-brown (Figs. 22, 23), ventral surface cream white (Fig. 24). Submentum trapezoidal, posteriorly broadly rounded and without conspicuous central posterior tip (Fig. 24).

Thorax. Pronotum dark brown (Fig. 25). In total, 110–130 setae of varying lengths distributed over anterior two-thirds of each pronotal half. In total, 78–89 setae of varying lengths distributed over anterior two-thirds of each mesonotal half (Fig. 25). Metanotal setation consisting of 5–6 setae in each setal area 1 (sa 1), 1 seta in each sa 2, and 6–9 setae in each sa 3 (Figs. 25, 26). Setose area of coxa with less and shorter setae than in H. megalochari . Propleural anterior process relatively short, with blunt tip (Fig. 27).

Abdomen. Segment VIII with row of 18–22 tubercula per side.

Case. Case diameters ranging from 3.2 x 2.9 mm to 4.4 x 3.5 mm, height 2.0–2.2 mm (n = 4; Figs. 28, 29).