Stonefly Species Isoperla denningi (Yellow Sallies)

Source: The Isoperla Of California (Plecoptera: Perlodidae); Larval Descriptions And A Key To 17 Western Nearctic Species

Male larva. Body length of mature larva 11 – 12 mm. Dorsum of head with contrasting pigment pattern and fine dark clothing setae, anterior frontoclypeus margin unpigmented; light M shaped pattern anterior to median ocellus usually not connected to light frontoclypeus area, median longitudinal light band thin with parallel margins, lateral thin arms directed posterolaterally, extending to antennal bases; posterior ocelli with completely enclosed small light areas along outer lateral margins; interocellar area variable, usually its entire area lighter than surrounding dark pigment, partially filled with indistinct light brown pigment, extending past posterior ocelli and connected to light area below occipital spinulae band, occasionally interocellar area partially filled with surrounding dark pigment and not connected to light area of posterior head capsule; occiput with irregular spinulae band extending from below eye to near median epicranial suture, partially enclosed by light brown pigment (Fig. 7 a). Lacinia bidentate, total length 756 – 1093 µm (Figs. 2 e, 7 e- h, Tables 2 - 4); submarginal row (A + B) with 3 – 4 setae, groups A-B interrupted by gap below subapical tooth (SAT) inner margin (Fig. 7 g); 1 submarginal seta (A) inserted at base of apical tooth (AT) inner margin, plus 1 thin marginal seta (TMS) adjacent to AT inner margin, sometimes obstructed from view by AT, submarginal seta (A) or broken, and 1 dorsal seta (DS) located below SAT inner margin, partially obstructed by SAT or submarginal setae (B) (Figs. 7 g-h); 2 – 3 submarginal setae (B) located past SAT inner margin (Figs. 7 g-h); 9 – 13 marginal setae (C) initially long-stout and widely spaced, last few shorter and widely spaced, sometimes borne from ventral or dorsal surface or broken with visible sockets (Fig. 7 e); 11 – 34 ventral surface setae (D) scattered below submarginal and marginal setae, ending posteriorly at approximately ¾ the inner lacinia margin length and concentrated in apical half, occasionally a few setae located below submarginal row striated (Fig. 7 f); dorsal surface setae (DSS) usually absent, sometimes last few marginal setae (C) form a short dorsal row (Fig. 7 f – arrow). 15 – 25 minute scale-like spinulae on and along dorsal inner-lateral margin in basal half. Galea with 35 – 48 setae in thick ventral band, apex with 4 – 5 setae. Maxillary Palp segments 2 – 3 with curved, apically pointed setae. Pronotum with thin, median light area bordered by irregular dark longitudinal bands with adjacent light rugosites; discs each with dark comma shaped lateral areas and fine dark clothing setae restricted to areas of dark pigmentation, lateral margins with broad light bands (Fig. 7 b). Mesonotum and metanotum with contrasting pigment pattern and fine dark clothing setae (Fig. 7 c). Legs with numerous fine golden clothing setae and scattered erect spines on outer surface of femora, erect spines longest and concentrated on dorsal surface; fine silky setae numerous and continuous on dorsal surfaces of femora and tibia (Fig. 20 e); tibia with faint transverse bands near proximal end. Abdominal terga with two distinct longitudinal dark stripes; wide light median longitudinal band bisected with indistinct light brown median pigment band; lateral pair of dark longitudinal stripes not extending to lateral margins; numerous fine light clothing setae and erect spines scattered dorsally; posterior margin with scattered long and numerous short spines in a concentrated row (Fig. 7 d).

Source: The Isoperla Of California (Plecoptera: Perlodidae); Updated Male Descriptions And Adult Keys For 18 Western Nearctic Species

Male. Aedeagus: sclerotized posterior process present; body with two posterobasal lobes, one large posteroapical lobe, and one dorsolateral pair of rounded lobes (Fig. 5 a); sclerotized process length <0.5 mm, recurved and rod-like, apex clavate in lateral view (Fig. 5 a), bifurcate in posterior view, lateral apices short and rounded (Fig. 5 b), and width of expanded apicolateral lobes 0.09 - 0.10 mm. Abdominal terga 8 - 9, 9, 9 - 10: without stout spinulae or long stout setae. Posterolateral margins of at least abdominal segment 8 with scale-like setae clustered in brushes of several setae. Paraprocts: curved dorsally, length if straightened subequal to combined first and second cercal segments, tapering gradually to blunt apices (Fig. 5 c). Vesicle: pedunculate, length subequal to width, constricted near base with curved lateral margins, wider and rounded at apex (Fig. 5 d).