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

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

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington
This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for this one.
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.

Mayfly Species Leptophlebia johnsoni (Black Quills)

Where & when

Time of year : June

In 18 records from GBIF, adults of this species have been collected during June (67%), July (28%), and May (6%).

Species Range

Nymph biology

In Matching the Hatch, Ernest Schwiebert writes:

The nymph ranges freely about the bottom and is a common trout food.


There is little mention of this species elsewhere.

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.

Male Spinner

Body length: 9 mm
Wing length: 8-9 mm

This is a handsome, shining brown species with whitish mid-abdomen, conspicuously ringed tails and brown-tipped wings; head, thorax, and basal segment of abdomen shining blackish-brown above, paler on the sides; fore legs brownish, middle and hind legs paler especially toward the tarsi. Wings hyaline except for a faint brown apical cloud that is heaviest on the stigmatic region. Costal cross veins obsolete, except in the stigmatic region where they are numerous, oblique, sometimes forked. The subcostal cross veins in this region are few and strong and erect.

Abdomen white on segments 2 to 7 with black dots on the spiracles and yellow ganglia showing through the skin beneath; on the lateral margins there is sometimes a faint wash of brown and there is sometimes a still more faint cloud of brown on the mid-dorsum, especially on segment 7; segments 8-10 are brown above with chalky white streaks in old males at the sides, that extend rearward on the base of the forceps. Forceps white, four-jointed, the three small terminal joints successively more minute, and more or less deciduous. Penes long, yellow, their tips surpassing the principal bend of the forceps, separated by a Y-shaped notch; the reflexed spurs are long, at first convergent then bent rearward and parallel to their tips; the apical notch between the triangular divisions of the 9th sternite is unusually narrow (see fig. 131). The tails are distinctly ringed with rich red brown on the joinings of all the segments.

Described as L. gracilis

Body length 6-7 mm, wing length 5.5-6.5 mm

This is a dainty, pale brown, yellow-legged species, with the middle abdominal segments whitish, cross-barred with pale brown. Head in life orange, including the upper eye. Lower eye and basal rings of ocelli blackish.

Thorax reddish brown or fawn colored with paler marginal lines on the prothorax, in the notal groove, before the wing roots, and in the pleural sutures. Legs pale yellowish, darker on front femora; all with pale tarsi. Fore legs a little longer than the body. Wings sub-hyaline, tinged with brown toward the front by reason of the heavier veins in that portion of the wing, wholly hyaline toward the hind angle. Costal cross veins wanting before the bulla; those in the stigmatic area not very numerous, strongly aslant, and occasionally anastomosing.

Abdomen slender, pale reddish brown toward the ends, whitish in the middle portion, with dorsal cross bands of fawn color overspreading the apical half of segments 3 to 6. On the ventral side the yellow ganglia show through the translucent skin. The spiracles and the extreme apical dorsal margins of segments 8 to 10 are hair-lined in black. Tails subequal, whitish, with joinings of segments narrowly ringed with reddish. Forceps of the male four-jointed, white; penes red, rather narrowly linear and straight with a deep parallel-sided cleft between, each with a minute and very inconspicuous terminal tooth, and with a long slender reflexed spur that reaches proximally nearly to the end of the cleft (see fig. 131). Legs yellow beyond the pale reddish brown femora.

Female Spinner

The female is paler than the male on head, thorax and legs, darker on the abdomen, where the middle segments are only a little paler than the end ones, and that mainly on the ventral side. The 9th abdominal sternite is produced beyond the tip of the 10th in a transparent triangular lobe that is divided by a median apical excision in equilateral-triangular form.

Described as L. gracilis

Body length 6-7 mm, wing length 5.5-6.5 mm

In the female the entire dorsal surface is light reddish brown with the abdominal tergites slightly darker.

Dun

Described in Needham et al (1935) as Leptophelbia gracilis

The subimago in both sexes has wings, feet, and tails of a dull, smoky-brownish color.


Start a Discussion of Leptophlebia johnsoni

References

Mayfly Species Leptophlebia johnsoni (Black Quills)

Taxonomy
Species Range
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