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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.

Chironomidae (Midges) True Fly Adult Pictures

This extremely tiny fly was puzzling to identify. I collected it from a sparse mating swarm just above the surface of the river. It just doesn't have the "look" I'm used to seeing in Chironomids, but the key characteristics in Merritt, Cummins, & Berg point that way.

-Maxillary palp apparently with 4 segments, antenna with 6
-I can't see any ocelli and wing venation doesn't seem to match Axymyiidae
-Costa definitely ends at or near apex of the wing (pictured)
-Obvious characteristics and wing venation rule out a few other things
-Simuliidae seems like a possibility due to the broad wings, but bugguide says they're supposed to have more antennal segments (eleven, though a different source says some have ten, at least in the Southern Hemisphere).
-Postnotum with median longitudinal groove (pictured) rules out Ceratopogonidae

So my guess is some kind of chironomid from a genus that doesn't have the classic midge look. There are some like that.

This true fly was collected from the South Fork Snoqualmie River in Washington on May 22nd, 2022 and added to Troutnut.com by Troutnut on May 24th, 2022.

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