Identify this bug

[Cowlitz Bottomfeeder]

At 1000 this morning, a popular Cascade Lake at 4500 feet was carpeted with these insects. The hatch was over. Didn’t see any rises. Size #22-24 if it was a fly pattern.

 

[Taxon]

Hi Cowlitz Bottomfeeder-

It appears (to me) to be a mayfly imago of genus Caenis.

 

[Cowlitz Bottomfeeder]

Hi Cowlitz Bottomfeeder-

It appears (to me) to be a mayfly imago of genus Caenis.

Thank you very much. I think I’ve seen that many years ago on Lenice.

 

[Taxon]

Thank you very much. I think I’ve seen that many years ago on Lenice.

And I've also seen it many years ago on Dry Falls. Incidentally, although most flyfishers probably believe that Callibaetis are the most populous lake-resident mayflies in the USA, Caenis actually are, and by a ratio in excess of 4/1. Please see Lakes Biotic Survey.