Hydropsyche askalaphos Malicky & Chantaramongkol 2000

Seetapan, Kriengkrai & Prommi, Taeng On, 2022, The larvae of caddisfly species (Insecta, Trichoptera) in northern Thai streams and their relationships to environmental variables, Zootaxa 5222 (4), pp. 301-324 : 312-315

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.

Figures

FIGURES 20–26. Larva of Hydropsyche askalaphos Malicky & Chantaramongkol 2000: 20, larval habitus, right lateral; 21, head, dorsal; 22, head, ventral; 23, frontoclypeal apotome, dorsal; 24, labrum, dorsal; 25, mandibles, ventral; 26, submentum and anterior ventral apotome, ventral.

FIGURES 27–34. Larva of Hydropsyche askalaphos Malicky & Chantaramongkol 2000: 27, pronotum, dorsal; 28, mesonotum, dorsal; 29, metanotum, dorsal; 30, right pleuron, foretrochantin (arrow indicating lower fork), and foreleg, right posterolateral; 31, right midleg, right posterolateral; 32, right hind leg, right posterolateral; 33, prosternites, ventral; 34, abdominal segments I–III with dorsal scale-like setae and hair-like setae, right lateral.

FIGURES 35–36. Larva of Hydropsyche askalaphos Malicky & Chantaramongkol 2000: 35, sterna VIII and IX and anal prolegs, ventral; 36, tergum IX (with small lateral sclerite and large subdorsal sclerite) and anal prolegs, right lateral.