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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 Holocentropus (Polycentropodidae) Caddisfly Larva from the Yakima River in Washington
This one seems to tentatively key to Holocentropus, although I can't make out the anal spines in Couplet 7 of the Key to Genera of Polycentropodidae Larvae nor the dark bands in Couplet 4 of the Key to Genera of Polycentropodidae Larvae, making me wonder if I went wrong somewhere in keying it out. I don't see where that could have happened, though. It might also be that it's a very immature larva and doesn't possess all the identifying characteristics in the key yet. If Holocentropus is correct, then Holocentropus flavus and Holocentropus interruptus are the two likely possibilities based on range, but I was not able to find a description of their larvae.
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 is a small tributary of the East Fork of the Iron River in Bayfield County, Wisconsin. I visited it once and collected some bugs at road below a (former?) fish hatchery, but it looked too small to fish comfortably and I didn't try to catch anything.

Closeup insects by Troutnut from Schacte Creek in Wisconsin

Baetidae (Blue-Winged Olive) Mayfly Nymph from Schacte Creek, Bayfield County in Wisconsin
This Baetis nymph is quite a bit larger than any of the others I found in winter 2004. Abdomen segment 5 is only slightly pale while 9 and 10 are quite pale. The tail is banded at the tip. Its body measures about 9mm long. It's much larger than the other Baetis specimens I collected, and it has quite well-developed wingpads.

It's most likely a mature nymph from a very early-hatching brood. It comes from the headwaters of a very small, very spring-fed Lake Superior tributary, which wasn't at all frozen despite very frigid temperatures and 3 feet of snow on the ground.
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