Hydropsyche askalaphos Malicky & Chantaramongkol 2000

(Figs 20–36)

Larva: Total length 16.0– 16.5 mm (n = 10). Overall body shape as usual in Hydropsychidae . Head and notal sclerites reddish-brown to dark brown (Fig. 20).

Head: Head capsule length 1.22–1.26 mm; width 1.20–1.22 mm. Dorsum of head reddish-brown, areas around eyes light yellow, occiput with pale muscle scars (Fig. 21). Long, black, erect, truncate peg-like setae (tp) dorsally and laterally, tapered setae on anterior half, with acuminate peg-like setae (ap) on dorsal and lateral regions in anterior three-quarters. Frontoclypeal apotome strongly indented anterolaterally in anterior 2/3; anterior margin concave laterally and convex medially and asymmetrically incised on right 1/3, with 4 yellow areas arranged as cross: small anterior spot, pair of oblique oval spots near midlength, large posterior spot (Figs 21, 23). Ventral surface of head reddish-brown (Fig. 22). Labrum reddish-brown; apically rounded in dorsal view; bearing welldeveloped, golden brown, pectinate, anterolateral setae and long, stout, dark, dorsal setae (Fig. 24). Mandibles dark brown, asymmetrical: left and right mandibles each with 1 apical tooth and 1 mesal tooth, outer surfaces of both mandibles with scattered setae, left mandible with mesal tuft of long setae (Fig. 25). Submentum reddish-brown, with deep anteromesal cleft, anterolateral margins on either side of cleft with long setae (Fig. 26). Anterior ventral apotome broadly triangular; posterior ventral apotome small, oval (Fig. 26).

Thorax: Nota yellow-brown (Figs 27–29) densely covered with peg-like setae similar to those on dorsum of head. Prosternite brown, transverse, narrow, with dark anterolateral corners and dark band across posterior half; with pair of large, posterolateral sclerites pale mesally and darker laterally (Fig. 33). Foretrochantins deeply forked (Fig. 30, black arrow indicating lower fork). Forelegs stouter than other legs, each with numerous setae on posterior surface of coxa; trochanter and femur with row of long setae on ventral margins (Fig. 30). Mid- and hind legs similar in size, shape, and structure; with stout setae on posterior surfaces of trochanters and femora (Figs 31–32). Mesosternum with one pair of single-stemmed gills and metasternum with 2 pairs of single-stemmed gills; gills each bearing approximately 60 lateral filaments.

Abdomen: Abdominal segments I–IX densely covered with brown, scale-like and hair-like setae (Figs 20, 34). Sternum I with 2 pairs of bifid-stemmed gills. Segments II–V each with one pair of submedian ventral gills. Segments II–VII each with one pair of sublateral gills each arising from common base (Figs 20, 34). Sternum VIII with pair of small, triangular sclerites bearing spike-like setae. Sternum IX with pair of large, triangular sclerites bearing spike-like setae with conspicuous bases. Tergum IX with pair of small lateral sclerites and pair of large subdorsal sclerites (Figs 35–36). Anal prolegs each with bent apical claw, spike-like setae present on dorsal and ventral surfaces, subapicodorsal fan of long setae (Figs 35–36).

Material examined: THAILAND: PHAYAO PROVINCE: Phu Sang National Park, Nam Phuai Bon, 446 m a.s.l., 19°39'55.8"N, 100°22'37.4"E, 23-i-2021, 14 larvae, 1 male pupa, leg. Prommi ; Nam Phuai Lang, 474 m a.s.l., 19°40'27.9"N, 100°23'20.2"E, 24-i-2021, 18 larvae, 2 male pupae, 1 male adult, leg. Prommi ; Nam Yuan Ton, 510 m a.s.l., 19°30'02.5"N, 100°27'01.6"E, 25-vi-2021, 12 larvae, 1 male pupae, 1 male adult, leg. Prommi ; Nam Yuan Huai Pum, 495 m a.s.l., 19°31'17.5"N, 100°24'25.0"E, 26-vi-2021, 36 larvae, 2 male pupae, 2 male adults, leg. Prommi.