Hydromanicus malayanus Banks 1931

Prommi, Taeng On & Permkam, Surakrai, 2015, Larvae of Hydromanicus (Insecta: Trichoptera: Hydropsychidae) from Thailand, Zootaxa 3914 (4), pp. 467-482 : 468

Hydromanicus malayanus Banks 1931

( Figs. 1–18 )

Larva: Total length 11.0–12.00 mm (n=10). Overall body shape typical for Hydropsychidae .

Head: Head capsule length, 1.19–1.22 mm; width, 0.94–1.03 mm. Dorsum of head brownish ( Fig. 2 ). Dorsal and lateral portions of head covered with long, black, truncate peg setae, with tapered setae in anterior three-fourths ( Figs. 13–14 ). Frontoclypeus covered with same setae. Frontoclypeal apotome strongly indented laterally; anterior margin convex medially ( Figs. 2 , 13 ). Ventral surface of head brownish, with stridulatory lines narrowing posteriorly; posterolaterally with group of muscle scars ( Fig. 3 ). Mandibles dark-brown with 2 apical and 3 mesal teeth, left mandible with well developed setal brush; outer surfaces of both mandibles with scattered setae ( Fig. 4 ). Labrum brown; rounded in dorsal view; bearing well-developed, lateral, golden-yellow, pectinate setae and long, stout, dark, dorsal setae, with one pair of longer, dark anteromesal setae ( Fig. 5 ). Submentum brown; lacking anteromesal cleft; anterior margin concave ( Fig. 3 ). Anterior ventral apotome broadly triangular; posterior ventral apotome small, triangular ( Fig. 3 ).

Thorax: Nota brownish ( Figs. 6–8 ) covered with same setae as on dorsum of head ( Figs. 13–14 ). Prosternite brown; broadly transverse; dark band along posterior margin; with pair of large sclerites ( Fig. 9 ). Foretrochantin forked; dorsal branch as long as ventral branch ( Figs. 1 , 10 ). Forelegs stouter than other legs, each with femur widened; femur with long setae in ventral margin; tibia and tarsus with rows of short, stout setae ( Fig. 10 ). Mid- and hind legs similar in size, shape, and structure; with dense setae on mesal surface of coxa through tarsi ( Figs. 11–12 ). Mesosternum with one pair of gills; metasternum with 2 pairs of gills; gills consisting of central stem bearing many lateral filaments ( Figs.1 , 17 ).

Abdomen: Abdominal segments with dense brown, diamond-shaped setae in various sizes ( Figs. 1 , 15–16 ). First sternum with 2 pairs of gills with adjacent bases. Segments II–VI each with 2 pairs of lateral gills and 1 pair of median gills ( Fig. 1 ). Sternum VII without gills. Sternum VIII with pair of small, subtriangular sclerites bearing spike-like setae. Sternum IX with pair of large, sclerotized triangles bearing spike-like setae emanating from prominent sockets ( Figs. 1 , 18 ). Tergum IX with pair of small lateral and dorsolateral sclerites. Anal prolegs each with bent claw and cluster of long bristles, spike-like setae present on dorsal surface ( Fig. 1 ).

Material examined: THAILAND. SONGKHLA Prov.: Ko Hong Nature Preserve, 50 m. 09°51' N, 098°37' E, 27-vi-2006, Prommi, 12 larvae, 3 male pupae, 1 male adult; same locality, 06-viii-2006, Prommi, 18 larvae, 3 male pupae, 1 male adult; same locality, 06-vii-2006, Prommi, 18 larvae, 3 male pupae, 4 male adults; same locality, 12- ix-2006, Prommi, 18 larvae, 3 male pupae, 1 male adult; same locality, 01-x-2006, Prommi, 18 larvae, 3 male pupae, 1 male adult; same locality, 06-xi-2006, Prommi, 18 larvae, 3 male pupae, 1 male adult; same locality, 14- xii-2006, Prommi, 18 larvae, 3 male pupae, 2 male adults; same locality, 03-i-2007, Prommi, 18 larvae, 3 male pupae, 2 male adults; same locality, 10-ii-2007, Prommi, 18 larvae, 3 male pupae, 3 male adults; same locality, 26- iii-2007, Prommi, 18 larvae, 3 male pupae, 2 male adults; same locality, 22-iv-2007, Prommi, 18 larvae, 3 male pupae, 2 male adults; same locality, 05-v-2007, Prommi, 18 larvae, 3 male pupae, 1 male adult; same locality, 09- vi-2007, Prommi, 18 larvae, 3 male pupae, 1 male adult.

Figures

FIGURES 1 – 5. Larva of Hydromanicus malayanus: 1, larva, right lateral; 2, head, dorsal; 3, head, ventral; 4, mandibles, dorsal; 5, labrum, dorsal.

FIGURES 6 – 12. Larva of Hydromanicus malayanus: 6, pronotum, dorsal; 7, mesonotum, dorsal; 8, metanotum, dorsal; 9, prosternum (arrow), ventral; 10, right pleuron, foretrochantin (arrow), and foreleg, right lateral (posterior); 11, right midleg, right lateral (posterior); 12, right hind leg, right lateral (posterior).

FIGURES 13 – 18. SEM images of Hydromanicus malayanus: 13, head, dorsal; 14, setae on surface of head, dorsal; 15, setae on abdominal segments, dorsal; 16, setae on abdominal segment III, dorsal; 17, ventral submesal abdominal gills of segment I, ventral; 18, sterna VIII and IX, ventral.