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 Helopicus (Springflies)
Genus Range
Specimens of the Stonefly Genus Helopicus
1 Female Adult
I caught this female during her egg-laying flight.
Discussions of Helopicus
Helopicus subvarians (Stonefly) common in New York waters!
6 replies
Posted by Walleye on Jan 7, 2014
Last reply on Jan 9, 2014 by Entoman
I have observed the Helopicus subvarians (springtime stonefly) for over 30 years on many of New Yorks Rivers, such as Beaverkill/Willowwemoc, Ausable (both east and west branch), West Canada Creek, and several others. Most of this time I believed it to be Acroneura nigrita ( Black Willow Stonely) as described by Ernest Schwiebert (Nymphs). Very distinct about the coloring of this Staonely is the last (rearward) sternites are very yellow (Ausable almost orange) while the riest is mostly black top and bottom. The thorax is again very distinctly marked with yellow (orange) with black on top. It is a most beautiflul stonefly, and is see it in May and June. It is well represented by the Montana Nymph is Black with yellow.
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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.
Stonefly Genus Helopicus (Springflies)
Taxonomy
Species in Helopicus: Helopicus nalatus, Helopicus subvarians
1 species (Helopicus bogaloosa) isn't included.