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.
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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.
- 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.
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Stonefly Genus Capnia (Little Snowflies)
This is one of the most common genera of Capniidae.
Genus Range
Specimens of the Stonefly Genus Capnia
1 Adult
Start a Discussion of Capnia
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.
- Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.
Stonefly Genus Capnia (Little Snowflies)
Taxonomy
Species in Capnia
Capnia gracilariaLittle Snowflies
0
0
Capnia inyoInyo Snowflies
0
0
Capnia nanaDwarf Snowflies
1
2
Capnia umpquaUmpqua Snowflies
0
0
Capnia venturaVentura Snowflies
0
0
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.