Stonefly Species Podmosta weberi (Tiny Winter Blacks)

Source: Further Descriptions Of Western North American Podmosta Larvae And Their Separation From Ostrocerca Larvae (Plecoptera: Nemouridae) (Figs. 8, 12 a, 19 - 22, 27, 32, 36, 38, 41, 49, 50)

Characters. Body length male 4.2 - 4.5 mm, female 4.5 - 5.5 mm, light brown with indistinct dark mottled pattern on occiput. Antennal segments approximately 42, head capsule width 0.80 - 0.90 mm; eyes large, head wider than pronotum. Gills absent. Mandibles with 5 or 6 apical teeth; right mandible with raised molar pad (Figs. 19, 21) that grinds against the opposing depressed molar cup of left mandible (Figs. 20, 22), molar cup with outer (dorsal) comb of curved teeth (Figs. 20, 22). Laciniae triangular, typical of genus, palmate, with scalloped palm surface, 7 - 9 finger-like apical teeth, apicodorsal comb of about 10 long, acute-pointed bristles and apicoventral comb of about 8 short, acute-pointed bristles (Fig. 27). Pronotum bearing scattered short bristles and sensillae on disc surface and lacking distinct lateral fringe (Fig. 32). Wing pads bearing scattered, short bristles and tuft of short bristles on anterolateral corners (Fig. 36). Femora bearing scattered short bristles and hairs over dorsal surface, longer bristles apicodorsally (Fig. 38). Tibiae bearing scattered short bristles (Fig. 38) and few (5 - 7) posterior silky fringe hairs. Mesosternal Y-ridge closed anteriorly as in Stewart & Stark (2002; Fig. 9.16 E). Abdominal terga bearing macrotrichia and microtrichia scattered on intercalary surface and forming a posterior fringe (Fig. 41). Sexual dimorphism evident; males with raised tergum 10 in lateral view, and developing hypoproct on sternum 9 (Fig. 12 a). Cercal segments 22 - 24, cercomeres 1 - 10 bearing apical whorls of stout bristles, fine hairs and sensillae, bristles about 0.25 times length of their segment (Fig. 49). Middle and anteapical cercomeres bearing whorl bristles 0.35 - 0.60 times length of their segment, with anteapical ones longest ventrally, and with 2 - 4 intercalary bristles and/or fine hairs about 0.25 times length of their segment, all as seen laterally 9 (Fig. 50). Diagnostic characters: cercal setation as described (Figs. 49, 50).