Amphipsyche gratiosa Navás 1922

Peumwarunyoo, Pronthip & Prommi, Taeng-On, 2013, Larvae of Amphipsyche species (Trichoptera: Hydropsychidae) from Thailand, Zootaxa 3635 (3), pp. 251-260 : 252-256

Amphipsyche gratiosa Navás 1922

Head: Dorsum of head yellow to dark-brown. Frontoclypeal apotome and dorsal surface of head flattened. Surface of head dark-brown dorsally, with transverse yellow mark on frontoclypeal apotome. Muscle scars posterodorsally. Head with few long bristles close to eyes. Head with numerous tapered setae on dorsal regions ( Figs. 2 , 16 ). Frontoclypeus with anterior margin concave and entire; triangular posterior end touching carina. Anteclypeus with 4 large brown sclerites basally ( Fig. 2 ); distal part of anteclypeus membranous. Lateral and ventral surfaces of head yellowish. Genae ventrally with stridulatory lines near mid length close to mid-ventral suture ( Fig. 3 ). Labrum with large membranous basal region and large brushes on apicolateral lobes; anterior margin with dense fringe of hairs and rows of short, erect, clavate setae ( Fig. 4 ). Anterior ventral apotome subtriangular with lateral lobes rounded and posterior tip pointed; posterior ventral apotome small and spearhead-shaped ( Fig. 3 ). Submentum large, triangular, with bristles on its apical margin. Dorsal and ventral ridges of both mandibles each with bristles on outer margins; ventral blade of each mandible mesally with conspicuous, blunt, basal tooth and irregular, broad, apical incisor ( Fig. 5 ).

Thorax: Thoracic nota light brown with numerous tapered primary setae ( Fig. 14 ). Pronotum divided into 2 sclerites separated by median ecdysal line, with pair of short anterior setae on either side of mid-line ( Fig. 6 ). Meso- and metanota each with median black mark on posterior margin: mesonotal mark large and crescentic, and metanotal mark small and irregular in shape. Meso- and metanotal sclerites each with 3 pairs of long primary setae ( Figs. 7–8 ). Mesosternum with pair of tracheal gills; metasternum with 2 pairs. Transverse prosternite with transverse brown stripe, posterior margin with large, triangular median sulcus ( Fig. 9 ). All legs stout, equipped with spines, bristles, and soft, tapered setae. Forelegs each with single, pointed trochantin and single coxal scraper on its inner margin ( Figs. 10–12 ).

Abdomen: Abdominal segments with numerous tapered setae ( Fig. 15 ). Abdominal segments I and II each with row of hooks on tergum. First segment with 3 pairs of gills on sternum ( Figs. 1 , 13, 17 ). Sterna II–VI each with 6 pairs of gills. Sternum VII with 5 pairs of gills. Sternum VIII with 2 pairs of gills. Sternum IX with pair of large ventral sclerites equipped with long bristles on posterior margins and row of bristles on each ventrolateral surface. Anal prolegs long and well-developed, each bearing cluster of long bristles and right-angled anal claw; dorsal surface of each proleg sclerotized ( Fig. 18 ).

Diagnosis: This species is easily and quickly recognized by a very conspicuous transverse yellow mark on the frontoclypeus apotome. In addition, this larva can be distinguished from that of A. meridiana by the following characteristics: Firstly, the central stalk of each abdominal gill has only a few lateral filaments. Secondly, the average head length and width of A. gratiosa is smaller than those of A. meridiana . In general, A. gratiosa is less robust and smaller than A. meridiana .

Material examined: THAILAND: Kanchanaburi Prov.: Huai Kayeng stream, 2-v-2009, Prommi, 39 larvae, 12 male pupae, 1 male adult; same locality, 2-vii-2009, Prommi, 37 larvae, 9 male pupae, 10 male adults; Huai U- Long stream, 2-vii-2009, Prommi, 29 larvae, 8 male pupae, 30 male adults.

Figures

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

FIGURES 13 – 18. SEM images of Amphipsyche gratiosa: 13, larva, right lateral view; 14, setae on pronotum, dorsal view; 15, setae on abdominal segments III, dorsal view; 16, head, dorsal view; 17, ventral submesal abdominal gills of segment I, ventral view; 18, anal prolegs, caudal view.

FIGURES 6 – 12. Larva of Amphipsyche gratiosa: 6, pronotum, dorsal view; 7, mesonotum, dorsal view; 8, metanotum, dorsal view; 9, prosternum (arrow point); 10, right foreleg, a right lateral view of the lateral (posterior) face with coxal scraper (arrow point); 11, right midleg, a right lateral view of the lateral (posterior) face; 12, right hindleg, a right lateral view of the lateral (posterior) face.