Isoperla sobria (Hagen)

(Figs. 15 a-d)

Perla sobria Hagen 1874 .

Holotype ♀, “ Colorado mountains .”

Perla ebria Hagen 1874 .

Holotype ♀, “ Colorado mountains .”

Isoperla sobria: Szczytko & Stewart 1979 .

Male. Aedeagus: sclerotized posterior process absent; body of aedeagus typically with one anterior lobe and a pair of conical dorsal lobes (Figs. 15 a-c); in one male collected in copula, a small posteroapical lobe was present (Figs. 15 a-b); one long median patch of spinulae along posterior margin (Figs. 15 a-c). 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 blunt points (Fig. 15c). Vesicle: lobe barely perceptible, at best represented by an area of lighter pigment (Fig. 15d).

Isoperla sobria is most similar to I. miwok (Table 1), with both included in the I. sobria complex (Bottorff et al. 1990). They differ most in the shape of the aedeagal spinule patch. In I. sobria, there is only one median patch on the posterobasal margin; in I. miwok, there is a posteroapical and a posterobasal patch, and the latter is concentrated into two nearly parallel bands. Isoperla sobria is distributed in higher elevation permanent streams in central to northcentral California. Isoperla miwok, as with I. acula and I. adunca, is usually associated with small intermittent streams of the Sierra Nevada foothills in north-central California, with one unconfirmed Lake County, Coastal Range location (Sandberg 2011b).