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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

Dorsal view of a Grammotaulius betteni (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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.
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Mayfly Species Paraleptophlebia associata

Where & when

In 4 records from GBIF, adults of this species have been collected during April (25%), March (25%), May (25%), and June (25%).

In 1 record from GBIF, this species has been collected at elevation of 450 ft.

Species Range

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: 7.5-8 mm
Wing length: 7.5-8 mm

A dark brown species, wings amber-tinted.

Head and thorax deep black-brown. Fore leg dark brown, middle and hind legs somewhat paler brown. Wings hyaline, tinged with amber color. Longitudinal veins light brown. Stigmatic area definitely brownish.

Abdomen brown; the anterior segments semi-translucent, the three posterior segments ruddier and opaque. Each segment is rather paler on the anterior margin. Posterior and lateral margins of the tergites blackish brown. Tails yellowish brown, darker at the base; joinings darker brown. Forceps light brown. Apical notch between penes lobes rounded, almost closed at the top by the approximated inner apical margins of the penes. Reflexed spur rather short, not as long as in Paraleptophlebia compar (now a synonym of P. associata), and rounded at the apex.

Described as P. compar

Body length 7.5 mm, wing length 7.5 mm

A rather pale brown species, resembling Paraleptophlebia californica in coloring, but like Paraleptophlebia associata in genitalia.

Head reddish yellow. Thorax reddish brown, the pleural sutures pale. A pale spot anterior to the mesothoracic scutellum. Notum tinged with yellow. Purplish black pencilings on the pronotum, and in an oblique line along the pleura from the base of the fore wing. Black marks at the base of the hind coxa. Legs pale whitish faintly tinged with yellow. Apical end of fore femur and base of fore tibia reddish brown. Wings hyaline. Longitudinal veins in anterior half of fore wing pale brown; other veins colorless. Stigmatic cross veins simple, somewhat slanting, 8-10 in number.

Abdomen pale with smoky markings. Segments 1-5, and the basal portion of 6, whitish and semi-hyaline. Apical segments opaque, yellowish. Posterior margins of tergites with a broad purplish grey band; lateral margins with faint smoky clouds. A small dark blotch in the postero-lateral angles. A purplish grey band, with a narrow black penciling, along the pleural fold. Faint indications of a narrow dark geminate mid-dorsal line on basal and apical tergites. A purplish mark on the posterior margin of each sternite, at the postero-lateral corner only. Tails greyish at base, silvery white at tips. Joinings in basal half purplish grey.

Forceps base pale reddish brown. Forceps brown at base, pale distally. Penes very similar to Paraleptophlebia associata, but with longer reflexed lobes (see fig. 135).


Start a Discussion of Paraleptophlebia associata

References

Mayfly Species Paraleptophlebia associata

Species Range
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