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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Dorsal view of a Kogotus (Perlodidae) Stonefly Nymph from Mystery Creek #199 in Washington
This one pretty clearly keys to Kogotus, but it also looks fairly different from specimens I caught in the same creek about a month later in the year. With only one species of the genus known in Washington, I'm not sure about the answer to this ID.
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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This topic is about the Mayfly Genus Litobrancha

This genus is very closely related to Hexagenia. Its only species, Litobrancha recurvata, can be quite important.

Example specimens

rochester mn

Posts: 133
Dryfly on Aug 29, 2009August 29th, 2009, 6:07 pm EDT
Sorry no photo
While out fishing I came across a big drake spinner. I think it might be Litobrancha Recurvata. 2 tails 17 mm body length, front pair of legs darker than back two, olive abdomen, darker thorax. Collected August 28th, which is relatively late for Litobrancha. Also could be Hexagenia Rigida or Atrocaudata.

Anyone know if Litobrancha or the Late Hexs are present in Southeast Mn?
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Aug 30, 2009August 30th, 2009, 10:21 am EDT

L. recurvata is recorded for MN, though the records appear to be from the northeastern corner. I haven't seen records of H. atrocaudata or rigida from MN, but they should probably be expected. They are recorded for WN and IA, with some records close to southeastern MN. H. limbata and bilineata are recorded for MN and are the most common Hexagenia species throughout most of the upper Mississippi River area. Although the peak of their hatch is usually earlier, stragglers of either species can be found into early September.

L. recurvata seems a bit unlikely. As you note, it is usually a fairly early emerger--around the end of May or beginning of June in my area, and probably June into early July in the upper Midwest. Although 17mm is just within the lower size range, this is the largest North American mayfly, with some specimens approaching 40mm. More significantly, I think you would have noticed the unusually dark wings. Even in the spinner stage, they have dark veins and a bronzy stain in the membrane of the wings.

If it was H. atrocaudata, you probably should have seen a dark border around the rear of the hind wing (though that dark border can also be found in some limbata, some rigida, and most bilineata).

rochester mn

Posts: 133
Dryfly on Aug 30, 2009August 30th, 2009, 1:21 pm EDT
Thanks for weighing in on my question. The hind wing's back edge is a bit darker. This is just the edge though. Does that sound like Atrocaudata?
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Aug 30, 2009August 30th, 2009, 3:26 pm EDT
Possibly. Is it a male? (Claspers will be present at the tip of the abdomen.) If so, and it's atrocaudata, the eyes should be quite close together on top of the head. Take a look at Jason's examples to see what I mean, and compare the dorsal and ventral markings to his:
If it's a female, the eyes will be smaller and further apart, but the abdominal markings should still be similar, as in this female dun:
(Sometimes the markings might not be quite as dark.)
rochester mn

Posts: 133
Dryfly on Aug 30, 2009August 30th, 2009, 4:07 pm EDT
It's a female. The colors have likely darkened considerably as it's two days old and now dead. It does have some of the same abdominal marking as the second male spinner. So it is most likely Hexagenia Atrocaudata. Thanks for your help Gonzo.
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Aug 30, 2009August 30th, 2009, 4:38 pm EDT
My pleasure, Dryfly. There are records of atrocaudata south of you in Winneshiek and Fayette counties in Iowa, so it seems quite reasonable.

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