Header image
Enter a name
Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Ventral view of a Hydropsyche (Hydropsychidae) (Spotted Sedge) Caddisfly Larva from the Yakima River in Washington
With a bit of help from the microscope, this specimen keys clearly and unsurprisingly to Hydropsyche.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Stonefly Species Isoperla miwok (Yellow Sallies)

Species Range


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

Diagnosis. Male larvae of Isoperla miwok are distinctive among all other California Isoperla species with 2 – 4 total submarginal (A + B) setae by the single lacinia submarginal (A) seta arising from near the middle of the base of the subapical tooth (Fig. 11 h).

Physical description

Most physical descriptions on Troutnut are direct or slightly edited quotes from the original scientific sources describing or updating the species, although there may be errors in copying them to this website. Such descriptions aren't always definitive, because species often turn out to be more variable than the original describers observed. In some cases, only a single specimen was described! However, they are useful starting points.

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

Male larva. Body length of mature larva 9 – 11 mm. Dorsum of head with contrasting pigment pattern and fine light clothing setae, anterior frontoclypeus margin unpigmented; light M shaped pattern anterior to median ocellus variable, usually connected to light frontoclypeus area by an apically narrowed median longitudinal light band, lateral thin arms directed posterolaterally, extending to antennal bases; posterior ocelli with partially enclosed large light areas along outer lateral margins; interocellar area variable, usually partially light, completely enclosed by dark pigment and extending posteriorly to epicranial Y-suture or sometimes open posteriorly and connected to posterior margin of head by thin light longitudinal band; occiput with irregular spinulae band extending from below eye to near median epicranial suture, not enclosed completely by dark pigment (Fig. 11 a). Lacinia bidentate, total length 622 – 888 µm (Figs. 2 i, 11 e- h, Table 2 - 4); submarginal row (A + B) with 2 – 3 setae, groups A-B interrupted by gap below subapical tooth (SAT) inner margin (Fig. 11 g); 1 submarginal seta (A) inserted near mid-base of SAT, half as stout at its base as first submarginal (B) seta, plus 1 thin marginal seta (TMS) adjacent to apical tooth (AT) inner margin, sometimes obstructed from view by AT or broken, and 1 dorsal seta (DS) located below SAT inner margin, partially obstructed by SAT (Figs. 11 g-h); 1 – 2 submarginal setae (B) located past SAT inner margin (Fig. 11 h); 5 – 7 marginal setae (C), initially long-stout and widely spaced, last few shorter and closer, blending into and difficult to differentiate from dorsal surface setae (Fig. 11 e); 7 – 15 ventral surface setae (D), scattered below marginal setae, ending posteriorly at approximately ¾ the inner lacinia margin length and concentrated in posterior half (Fig. 11 f); dorsal surface setae (DSS) continue from last marginal setae (C) as a single, laterally protruding, submarginal row (sometimes 2 – 3 setae thick) along inner-lateral margin, ending before or near posterior-most ventral surface setae (Fig. 11 f); 10 – 15 minute scale-like spinulae rarely present on and along ventral inner-lateral margin at middle of lacinia. Galea with 12 – 26 setae in sparse ventral row, apex with 2 – 4 setae. Maxillary Palp segments 2 – 3 with curved, apically pointed setae. Pronotum with large median light area bordered by thick dark comma shaped bands (typical of the Isoperla sobria complex) that fade rapidly in alcohol; discs each with fine light clothing setae, except over small light rugosites and lateral margins with broad light bands (Fig. 11 b); Mesonotum and metanotum with contrasting pigment pattern and fine light clothing setae (Fig. 11 c). Legs with numerous fine light clothing setae and scattered erect spines on outer surface of femora, erect spines longest and concentrated along dorsal surface; fine silky setae numerous and continuous on dorsal surfaces of femora and tibia (Fig. 20 i); distal femora and proximal tibia with faint transverse bands. Abdominal terga with three distinct longitudinal dark stripes; wide median longitudinal light band bisected with thin dark median longitudinal stripe; lateral pair of dark longitudinal stripes about as wide as median dark stripe, 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. 11 d).

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

Male. Aedeagus: sclerotized posterior process absent; body with one small posterior lobe, one large dorsal lobe and a pair of small pointed lobes on apicolateral margins (Fig. 9 a-b); a pair of long curved patches of spinulae on posteroventral surface (Fig. 9 b), and a broad patch of spinules on the posteroapical surface (Figs. 9 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 apices (Fig. 9 c). Vesicle: lobe barely perceptible, vestigial when present, widest at base with broadly rounded apex (Fig. 9 d).

Start a Discussion of Isoperla miwok

Stonefly Species Isoperla miwok (Yellow Sallies)

Species Range
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy