Wormaldia unispina Sun 1998

Hu, Yan-Li, Tsring, Samten, Wang, Bei-Xin & Sun, Chang-Hai, 2020, Descriptions of larvae of three Philopotamidae species from China (Insecta, Trichoptera), Zootaxa 4731 (4), pp. 509-521 : 515-517

Wormaldia unispina Sun 1998

( Figs 6 A–7E)

Description. Larvae (5th instar) Body length 8–10 mm (n = 3), body in alcohol white with head and pronotum yellow.

Head. Head capsule ( Fig. 6B ) yellowish brown; subrectangular in dorsal view, length about 1.5 times width, with surface smooth; frontoclypeal apotome ( Fig. 6C ) with anterior margin symmetrically convex, with 3 fine setae on each side; pair of dark brown transverse stripes located anterior of setae no. 6 between posterior angles of frontoclypeal sutures in posterior expansion; frontoclypeal sutures each about 5 times as long as coronal suture. Setae no. 4 located near anterolateral angle of frontoclypeal apotome; setae no. 5 posterior to tentorial pits; setae no. 6 posterior to aforementioned transverse stripes ( Figs. 6B, 6C ). In lateral view ( Fig. 6D ), subrectangular, smooth, with occipital margin notched; seta no. 13 spike-like, situated at midlength of gena. In ventral view ( Fig. 6E ) subrectangular, posterior margin with V-shaped excision, paired setae no. 18 stout and of same length as setae no. 13, located on center of each side; anterior ventral apotome triangular, with anterior margin straight and with each anterolateral angle slightly produced anterad; without transverse sulcus posteriorly. Eyes ( Fig. 6A, 6D ) oval, black, surrounded by faint yellow halo. Antennae ( Fig. 6H ) unusual, each supporting two separate rod-like spines and two tiny bristles, located at base of mandibles.

Labrum ( Fig. 6F ) white membranous, generally more or less T-shaped; anterior margin densely setose with small median notch; anterolateral angles rounded, setose with long hairs curved anterad; primary setae small, distance between setae no. 3 and no. 2 about 2 times distance between setae no. 2 and no. 1, setae no. 6 separated from setae no. 4 and no. 5 by transverse curved line.

Mandibles ( Fig. 6G 1 , 6G 2 ) of same colour as head and in some individuals slightly darker than head; each with outer surface bearing two bristles; inner margin smooth in basal half, serrate along 3/4 of length, subapical tooth very small, slightly larger and not recessed on right mandible.

Maxillae fused with labium ( Fig. 6H ). Each with cardo somewhat triangular, its inner angle produced into acute process covered by submentum, anterolateral margin concave, with seta; stipes membranous, bearing oblique blade-shaped sclerite with seta at midlength; fused lacinia-galea in ventral view triangular, lacinia with inner margin having two tufts of hairs; palpifer large, subrectangular in ventral view, with long subapical seta and small seta on inner margin; maxillary palp ( Fig. 6H ) four-segmented and slightly incurved in ventral view; first segment shortest, second and fourth segments equal in length, third segment as long as first and second segments combined.

Labium consisting of basal submentum and mentum, and distal labial part proper ( Fig. 6H ). Submentum trapezoidal, with one long black seta at each anterolateral angle; mentum membranous, contiguous with oblique sclerites from stipites. Labial part proper in lateral view ( Fig. 6D ) with lower angle producing into blunt process, dorsal margin heavily setose; in ventral view ( Fig. 6H ) somewhat tube-like, apically truncate; palpifer bar-shaped, labial palpi each 2-segmented.

Thorax. Pronotum ( Fig. 7A ) rectangular in dorsal view, sclerotized, of same colour as head, with posterior margin having V-shaped incision, its black border on each side disconnected from longitudinal curved black strips on lateral margin just above insertion of forecoxa ( Fig. 7B ); midlength with broad transverse constriction; anteriolateral setae longer than those at midlenth; six pairs of small midlength setae arranged in transverse row just behind aforementioned transverse constriction; at each side spine-like seta located above curved black strip. Proepisternum black, elongate, with apex furcate in lateral view, anterodorsal branch much longer than anteroventral branch; proepimeron semicircular, yellow, with anterior margin slightly concave; foretrochantin ( Fig. 7B ) fingerlike, apex pointed, upper margin produced into a triangular process at mid-length. Meso- and metanota ( Fig. 6A ) completely membranous, white.

Legs. Legs yellowish brown, sclerotized and subequal, but forelegs slightly shorter and darker than mid- and hind legs. Forecoxae ( Fig. 7C 1 ) with dorsal margin having one long bristle at midlength and one strong curved yellow spine beyond it; trochanters each 2-segmented, first segment short, with ventral margin about 1/3 as long as that of second segment; femora tubular, setose with spine-like setae; tibiae tubular, about 2/3 as long as femora, sparsely setose with spine-like setae; tarsi about same length as tibiae, each tapering from base to apex, with row of spine-like setae on ventral margin, otherwise sparsely setose ( Fig. 7D ); claws small, triangular, slightly curved downwards, each with apex pointed, ventral margin with conspicuous basal process and basal seta. Mid- and hind legs of same structure as forelegs, except for absence of strong bristles and spineson coxae.

Abdomen. Abdominal segments I–IX white, with sparse short setae. No lateral fringe present; without tracheal gills; segment IX in dorsal view with posterior margin concave. Anal prolegs ( Fig. 7E ) each with basal part soft, not sclerotized; medial part sclerotized and cylindrical, with two strong bristle apicodorsally; apical part triangular, articulated with apical sclerite within medial part; claw uncinate, with apex pointed, basodorsal surface setose.

Materials examined. CHINA, Zhe -jiang Province, Lin -an, Tian-mu Mountains: 1 larva, Che-shui-wu, 30.3558°N, 119.4522°E, Alt. 503.9 m, 10 Oct 2017 . Hu -zhou, An -ji County: 2 larvae, Dong-wu-cun, 30.4656°N, 119.5781°E, Alt. 348.7 m, 13 Oct 2017; collected by Yan-li Hu, Yu Wang, and Lang Peng. Yong -kang: 10 larvae, Tong-keng-cun, 28.9495°N, 120.2191°E, Alt. 212.51 m, 24 Mar 2018, collected by Yan-li Hu, Jin Gao, and Cong Wu ; 1 male, Tian-huang-ping Town , Chi-wu-li, 30.50°N, 119.60°E, Alt. 236 m, 12 May 2015, collected by Ji-hua Xu. Yu-yao County, Simingshan National Forest: 2 males, Chuan-di-wan, 29.7177°N, 121.0657°E, Alt. 729.54, 1 Aug 2016, collected by Ji-hua Xu.

Distribution. China (Zhejiang).

Figures

FIGURE 1. COI neighbor-joining diagram used to determine larva-male associations of Chinese Philopotamidae species. M. = male; L. = larva.

FIGURE 2. Chimarra sadayu Malicky 1993, larva. 2A, habitus, right lateral; 2B, head, dorsal; 2C, frontoclypeal apotome, dorsal; 2D, head, right lateral; 2E, head, ventral; 2F, labrum, dorsal; 2G1, left mandible, dorsal; 2G2, right mandible, dorsal; 2H, maxilla and labium, ventral. 1–18 = setae 1–18.

FIGURE 6. Wormaldia unispina Sun 1998, larva. 6A, habitus, right lateral; 6B, head, dorsal; 6C, frontoclypeal apotome, dorsal; 6D, head, left lateral; 6E, head, ventral; 6F, labrum, dorsal; 6G1, left mandible, dorsal; 6G2, right mandible, dorsal; 6H, maxilla and labium, ventral. 1–18 = setae 1–18.

FIGURE 7. Wormaldia unispina Sun 1998, larva. 7A, pronotum, dorsal; 7B, right side of pronotum, right foretrochantin, and right forecoxa, right dorsolateral; 7C1, right foreleg, posterolateral; 7C2, right midleg, posterolateral; 7C3, right hind leg, posterolateral; 7D, terminal portion of tarsus and claw of right prothoracic leg, posterolateral; 7E, left proleg, left lateral.