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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Female Drunella doddsii (Western Green Drake) Mayfly Dun Pictures
I still haven't got my good camera gear set up, but I wanted to get my first Alaskan bug specimen online, so I photographed this one with my point+shoot in the raft.
This mayfly was collected from the Gulkana River in Alaska on July 8th, 2007 and added to Troutnut.com by Troutnut on July 19th, 2007.
Discussions of this Dun
Anyone know your western Drunella species?
23 replies
Posted by Troutnut on Jul 19, 2007
Last reply on Apr 12, 2012 by Entoman
Which one is this? It's from a south-central Alaskan river.
great photo's
2 replies
Posted by Pauly on May 26, 2011
Last reply on May 26, 2011 by Troutnut
I would like to thank you for taking the time to photograph and post these beautiful pictures. I'm 64 years old, and an avid fly fisherman. My new hobbie is taking pics of mayflies, and I'm getting excited. I've got a new tripod on order, and an excellent camera. I would find it a pleasure to share my photo's with everyone.
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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.
Female Drunella doddsii (Western Green Drake) Mayfly Dun Pictures
Collection details
Location: Gulkana River, Alaska
Date: July 8th, 2007
Added to site: July 19th, 2007
Author: Troutnut
Date: July 8th, 2007
Added to site: July 19th, 2007
Author: Troutnut