Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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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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Wbranch on Mar 15, 2010March 15th, 2010, 7:12 pm EDT
"Most recent instantaneous value: 2,250 03-16-2010 02:15 EDT"
Was up to around 8500 cfs a few days ago WOW!
Was up to around 8500 cfs a few days ago WOW!
Catskill fly fisher for fifty-five years.
CaseyP on Mar 16, 2010March 16th, 2010, 1:13 am EDT
aren't stream gauges nifty? last year in the first week of May, a cloudburst raised the river overnight from around 500 cfs to nearly 1500. forewarned, we fished elsewhere!
"You can observe a lot by watching." Yogi Berra
Lastchance on Mar 17, 2010March 17th, 2010, 11:09 am EDT
Hi! I don't think we'll be fishing the Little J for awhile.I bet it will take a week to get to a fishable level.
Bruce
Bruce
Troutboomer on Mar 18, 2010March 18th, 2010, 12:10 am EDT
The "j" will be down to 1,000 CFS by Saturday noon, March 20th. There are only a few large pools that can be fished at this level even though the water clarity is already fair to good. I have seen flies (sulfers) hatch at over 900 CFS and fish feed on them, but this is unusual. Right now I am only seeing a few black stone flies and a few olives. Water temps are also still quite low. It was 38.3 degrees yesterday morning at 8am and rose to 45.9 degrees by 5 pm. I start looking for grannom caddis when temps reach 50 degrees by their mid-morning emergence time. This usually happens between the 12th and 16th of April although in 2005 I witnessed the first fishable grannoms on April 10th, the earliest date since I started keeping records in 1980. When the Redbuds bloom so do the grannoms!
Bill Anderson
Bill Anderson
Wbranch on Mar 18, 2010March 18th, 2010, 9:11 pm EDT
Moved post to "Fishing Reports".
Catskill fly fisher for fifty-five years.
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Mar 23, 2010
by Troutboomer
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