Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York

Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

Looking across Island Lake toward the Titcomb Basin—one of the popular crown jewels of the Wind River Mountains

From Island Lake in Wyoming

Stream photos

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Grammotaulius betteni (Northern Caddisfly) Caddisfly Larva Grammotaulius betteni (Northern Caddisfly) Caddisfly Larva

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.

12 Recently Added Photos

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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Stonefly Species Moselia infuscata (Tiny Winter Blacks)

Species Range

source

Identification

Species ID from GBIFthe Global Biodiversity Information Facility

Source: The Banded-Wing Moselia (Plecoptera: Leuctridae) Revisited

Diagnosis. This species lacks the pale wing bands found in most Moselia zonata and males have longer and narrower paraprocts than other Moselia. Females of the two species overlap in subgenital plate structure and cannot be reliably distinguished without the pale wing band character.

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.

Description from GBIFthe Global Biodiversity Information Facility

Source: The Banded-Wing Moselia (Plecoptera: Leuctridae) Revisited

(Figs. 1, 41, 43 - 52) http: // lsid. speciesfile. org / urn: lsid: Plecoptera. speciesfile. org: TaxonName: 4315Source: The Banded-Wing Moselia (Plecoptera: Leuctridae) Revisited

Adult habitus. Male forewing length 6.0 - 6.5 mm (n = 16), female 6.5 - 7.0 mm (n = 8). General body color dark brown, head brown on occiput and frons, but with a pale transverse band extending between compound eyes behind ocelli. Pronotum mostly pale brown, but with sutures dark brown, and with a large brown rugose area on either side of median suture (Fig. 43). Wings brown with conspicuous pale humeral and stigmatic markings, but subapical transverse pale band absent (Fig. 1). Tibiae almost entirely dark brown and without bands.

Male genitalia (n = 35). Typical of the genus but paraprocts long and slender with fin poorly developed and mostly sclerotized (Figs. 41, 44, 46 - 51). Paraproct body extending from base to fin apex 425 - 475 µm in length; greatest paraproct height across fin apex 94 - 125 µm. The apical digit on the paraprocts ranges from 138 - 154 µm in length.

Female subgenital plate (n = 2). Median lobe small, parabolic and poorly sclerotized. Large, heavily sclerotized lateral lobes triangular and broadly joined to posterolateral area of sternum 8 forming a continuous sclerotized margin. Median field of plate unsclerotized along a longitudinal stripe. Sternum 9 unsclerotized in a small area posterior to projecting subgenital plate (Fig. 45).

Egg. Unknown.

Larva. Described by Ricker (1943) and Stewart & Stark (1988, 2002).

Start a Discussion of Moselia infuscata

References

Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.