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.
3. Ok, if it's Hexagenia, which species is it? Of the three species reported from Quebec, H. bilineata can be eliminated over the lack of markings that appear as longitudinal striping in the hand. Of the two remaining, rigida is noted for its obvious yellow dorsal triangles, while limbata is noted for its high degree of variability and is by far the most common. Based on this I would say the specimen is most likely the latter. What is really interesting about the lateral photos is they show chevron markings pointing towards the thorax, which is very unusual. They normally point to the tails.
My opinion as to species? Hexagenia limbata.
I guess atrocaudata would be especially strange since I've always seen them in late August
Last I checked, I could use some Litobrancha for DNA. If they're from different places, that's even better. Keep me in mind, boys.
Perhaps I'm placing too much emphasis on distribution lists. Also, the definition of "very big" is relative.
but I don't have a lot of trust in distribution lists for judging the absence of a species
Now that you've adjusted the emergence date, I think everything points to atrocaudata. That's about the right time for them, but it would be quite late for limbata. Does anyone have an argument for limbata other than distribution and abundance?
Jason, I have witnessed a large, brown Hex spinner the end of July/early August on our "home" waters during some years. My notes back in the 80's I show it for several years just before Ephoron luekon started. I always assumed it was Hex. atrocaudata. Unfortunately, I don't have photos from back then.
Jason, I have witnessed a large, brown Hex spinner the end of July/early August on our "home" waters during some years. My notes back in the 80's I show it for several years just before Ephoron luekon started. I always assumed it was Hex. atrocaudata. Unfortunately, I don't have photos from back then.
John, I know exactly the hatch you're talking about. I've seen them on several rivers right around the time Ephoron is starting, and I've got a few specimens listed on this site under atrocaudata. I'm also sitting two feet from a 30-inch poster printout of one of my pictures of a male atrocaudata spinner. I'm quite confident in the ID... and they sure seem similar to this specimen from Quebec.
My most useful field ID trait for atrocaudata is to look for the dark, paired longitudinal dashes on the dorsal surface at the rear of the abdomen (between the angled hashmarks that meet the lateral midline). These paired dorsal dashes continue only faintly over the rest of the abdomen in some specimens, but they are usually very distinct on segments (7), 8, and 9. On rigida and many limbata, these marks are replaced by single, thicker dashes that form a "trident" shape in conjunction with the angled hashmarks, and can also be most prominent at the rear of the abdomen.
Oddly enough, I have never seen the dun, nor a shucked atrocaudata nymphal case on the water, just the spinners. Two of the largest trout I have ever hooked (never landed) on the river was with an extended-body comparadun when atrocaudata were fluttering around on the water.
Sadly, I don't have a direct dorsal view of the abdomen.