Davidius zallorensis Hagen

Davidius zallorensis Hagen View in CoL in Selys, 1878

( Figs 1a–n View FIGURE 1 ; 3a–b View FIGURE 3 ; 4a–b View FIGURE 4 ; 5a View FIGURE 5 )

Material examined

1 ♂ larva, 3 ♀♀ larvae, 15. VI. 2019, Sanjiacun Stream (25.51°N, 100.38°E, 2,129 m a.s.l), Fenyi Town, Dali City, Yunnan Province, China, Guo-Hui Yang leg. GoogleMaps ; 1 ♂ larva, 10. IV. 2019, same locality and collector GoogleMaps , 1 ♂ F-0, adult emergence 22. IV. 2019 .

Description

Moderately sized (19–24 mm length), body dark brown, flattened, with yellow setae ( Figs. 1a View FIGURE 1 ; 4a View FIGURE 4 ). Body surface with yellow–brown, fine hair, and lateral spines present on S7–9 ( Figs. 1a; 1k; 1m –n View FIGURE 1 ).

Head. Wider than long, about 1.6 times as wide as long. Labrum light brown, with short stiff setae on external surface. Clypeus dark brown and bare. Frons dark brown, with dense rows of short brown setae on distal margin ( Figs. 1a View FIGURE 1 ; 3a View FIGURE 3 ). Occipital margin protrusion large and distinct, protruding more laterally, with fine and short setae ( Figs. 1a View FIGURE 1 ; 3a View FIGURE 3 ). Antennae 4-segmented, inserted in front of the level of anterior margins of eyes, with fine long hairs on lateral margins; third segment long, elliptical in shape, and longest, about 2.3 times as long as wide, and flanked by fine, long yellow setae, its length nearly twice the length of the two basal segments combined, fourth segment shortest, length of each segment (mm): 0.47, 0.23, 1.44, 0.11 ( Fig. 1b View FIGURE 1 ). Compound eyes large, bulging laterally. Prementum trapezoid, long about 1.1 times as long as its widest part, widening from the 1/3 of basal, lateral edges covered with long, light brown setae; ligula shallowly convex, with four central teeth on apical margin, and with a dense row of long setae; labial palp brown, curved inwards; palpal lobe brown, conical, with nine short, irregular teeth on the inner side, pointed at the end; movable hook long, about 2.1 times as long as end hook ( Figs. 1c–d View FIGURE 1 ). Mandibles light brown, teeth black, formula: L 1234 0 a (m 1,2,3,4) b, with incisors 1> 2> 3> 4; R 1234 y a (m 1,2,3,4) b, with incisors 1> 2> 3> 4, a>b in both mandibles, incisor crest high, m denticles small, terete, semi-fused forming a continuous ridge ( Fig. 1e–h View FIGURE 1 ). Maxillae with seven sharp hooks covered with dense setae, and the whole maxilla covered with dense, long setae ( Fig.1i–j View FIGURE 1 ).

Thorax. Prothorax light brown and rectangular. Pterothorax light brown with yellow–brown hair-like setae at sides. Wing sheaths divergent, forewing sheaths reaching anterior margin of S4, hindwing sheaths reaching posterior margin of S4. Legs short and stocky, with stretched hind femur extending to one-half of S6. All legs with fine, yellow, dense setae.

Abdomen. Brown, covered with sparse tawny setae. Mid-abdomen expanded, maximum width on S5 ( Figs. 1a, 1k View FIGURE 1 ), without markings, and very flat. Dorsal hooks absent, posterolateral spines present on S7–9 ( Figs. 1a, 1k View FIGURE 1 ). Paraproct approximately 1.2 times longer than epiproct. Cerci short, one-half the epiproct’s length ( Figs. 1n View FIGURE 1 , 3b View FIGURE 3 ). Male with a pair of larger protuberances on the supra-anal plate, angular, distinctly protruding backwards ( Fig. 3b View FIGURE 3 ). The marks of male accessory genitalia are visible ventrally at S2–3 ( Fig. 1l View FIGURE 1 ); female gonapophyses rudimentary, visible at posterior margin of S8 ( Fig. 1m View FIGURE 1 ).

Measurements (mm). Larvae (in alcohol, N=5). Total length (including caudal appendages) 19–24; length of abdomen (including caudal appendages) 12–15; maximum width of head 4–5; length of hind femur 3–5.