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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.

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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Stonefly Genus Capnia (Little Snowflies)

This is one of the most common genera of Capniidae.

Where & when

In 47 records from GBIF, adults of this genus have mostly been collected during April (34%), March (21%), May (15%), February (13%), and June (11%).

In 8 records from GBIF, this genus has been collected at elevations ranging from 220 to 8648 ft, with an average (median) of 5338 ft.

Genus Range

Specimens of the Stonefly Genus Capnia

1 Adult

Start a Discussion of Capnia

References

Stonefly Genus Capnia (Little Snowflies)

Taxonomy
33 species (Capnia californica, Capnia cheama, Capnia coloradensis, Capnia confusa, Capnia elongata, Capnia erecta, Capnia excavata, Capnia fialai, Capnia giulianii, Capnia glabra, Capnia hitchcocki, Capnia jewetti, Capnia lacustra, Capnia licina, Capnia lineata, Capnia mariposa, Capnia melia, Capnia nearctica, Capnia ophiona, Capnia oregona, Capnia petila, Capnia promota, Capnia quadrituberosa, Capnia regilla, Capnia saratoga, Capnia scobina, Capnia sextuberculata, Capnia spinulosa, Capnia uintahi, Capnia valhalla, Capnia vernalis, Capnia willametta, and Capnia zukeli) aren't included.
Genus Range
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