Stonefly Species Isoperla bifurcata (Yellow Sallies)

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 one posterobasal lobe, one posteromedian lobe, one large dorsal lobe and one anterior lobe (Fig. 4 a); sclerotized process length> 0.5 mm, distal-projecting portion recurved and deeply bifurcate, apices of bifurcate arms with acute points and secondarily barbed (Figs. 4 a-c), and length of proximal-attached base (Fig. 4 a, 1) less than the total length of distal-projecting median arm (Fig. 4 a, 2), bifurcate arms (Fig. 4 a, 3), and apical tine (Fig. 4 a, 4). 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 abruptly to variable blunt to sharp apices (Fig. 4 c). Vesicle: pedunculate, length subequal to width, constricted near base with curved lateral margins, wider and rounded at apex (Fig. 4 d).