In the early 90s, my friend Eric Hoberg and I fished the McKenzie pretty much year around. We came across a strange stonefly hatch during a warm February day. The bugs were jet black with a yellow thorax. I asked Rick Hafele about the stonefly and he was well aware of the critter. He told me it is a relative of a Golden Stonefly but is smaller than a Golden Stone and larger than a Winter stone. It has a Latin name but Latin goes in one ear and out the other. (if I had to guess, I believe the bug is a Perlinodes aurea (Springfly), but I'm not sure on that one)
Eric and I tried tying a number of different patterns and finally came up with this one. It is the same colors as a Montana Stonefly Nymph so we called it a Dry Montana.
In Western Oregon, the hatches only last a few weeks and normally in February and March. They occur later in the year at higher elevations.
During one vacation fishing trip in July, Virginia and I were fishing the Lamar in YNP and found ourselves in the middle of a black and yellow stonefly hatch and experienced a banner day using the pattern shown above.
So, just in case, it is worth your while to tie up a few of these guys just in case you run into a hatch.
You can't miss them due to their contrasting colors.
Hook: TMC 5212, sizes 8-10
Tail: Black dyed coastal deer hair
Body: Black antron yarn
Wing: Black dyed coastal deer hair
Thorax: Yellow antron yarn
Hackle: Grizzly, dry fly quality