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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
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.

Dorsal view of a Grammotaulius betteni (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
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.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
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Neoephemera Mayfly Nymph Pictures

This specimen was sent to me for identification by Caleb Boyle, who did such a good job taking pictures of his mystery mayfly that, after identification, I asked him for permission to add it to this site, which he granted. This is great luck, since Neoephemera is a rare mayfly and it's unlikely I would ever have collected a specimen for the site myself.

Caleb collected it in mid-late May of 2004 either McDowell County or Ashe County in North Carolina, in a riffle less than two feet deep in a cold trout stream. He reared the nymph into a dun, whose wings appear in one of the photos below. He describes the specimen as follows:

Nymph exoskeleton:
Body: 16-17mm
Tails: 3, equal length, 13mm
Found on the surface of the water. The gill cover covers ab. segments 3-5.

Subimago:
Body: 16mm, dark brown/ olive
Tails: 3, equal length, 14mm
Wings: dark slate color, large hind wings.


I don't know to which species it belongs, but its size rules out the most common one in the genus, Neoephemera bicolor. It matches the size of Neoephemera purporea so that is a likely other possibility, but there are two other candidate species (Neoephemera compressa and Neoephemera youngi) about which I have no information, so I can't rule them out.

Disregard the camera, region, and exact date listed on these photos. I still need to update the site to accommodate user contributions which don't use my equipment.

This mayfly was collected from unknown in North Carolina on May 20th, 2004 and added to Troutnut.com by Troutnut on March 20th, 2007.

Discussions of this Nymph

A fun one for the bug lovers
2 replies
Posted by Troutnut on Mar 20, 2007
Last reply on Mar 13, 2008 by CalebBoyle
Caleb Boyle sent me this specimen to identify and, when I realized it was of a genus I'm unlikely to ever collect, I asked if I could put it up on the site. Read the specimen description for more info.

This is the first specimen by another photographer that I've included on Troutnut.com. Several excellent photographers have expressed interest in contributing, and I hope to start getting their pictures up this year in addition to mine. Before I start doing that on a large scale, I have a few days worth of programming I'll need to do to prepare the site. In the meantime, enjoy this one. :)

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References

Neoephemera Mayfly Nymph Pictures

Collection details
Location: unknown, North Carolina
Date: May 20th, 2004
Added to site: March 20th, 2007
Author: Troutnut
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