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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Rbpcaddis
Posts: 5
Posts: 5
Rbpcaddis on Jul 13, 2007July 13th, 2007, 4:54 am EDT
Fishing last Sunday on a spring creek to be left nameless, my buddy and I came to a pool where the trout were slashing and leaping out of the water chasing something. Typical Caddis activity right? We saw no adults on the water. or escaping into the air. Any other bugs that the trout would be chasing like that. This was around 11am to 12:30 pm. We then encountered the same type of action later in the evening around 6 pm to dark. Would the be chasing tiny emerging midge pupa so aggressively/
Taxon on Jul 13, 2007July 13th, 2007, 5:33 am EDT
Rjpcaddis-
It is named the Mystery Hatch!
Seriously, frantic feeding activity likely means the trout were chasing something reasonably elusive. It could have been insects making trial trips toward the surface film, but not actually yet ready to emerge. Some insects will do so for several days prior to emergence.
It is named the Mystery Hatch!
Seriously, frantic feeding activity likely means the trout were chasing something reasonably elusive. It could have been insects making trial trips toward the surface film, but not actually yet ready to emerge. Some insects will do so for several days prior to emergence.
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