The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
I agree an all brown or even a brown and orange bugger would be a great crayfish replica.
created by Russell Blessing, Pennsylvania Fly Tyer as early as 1967 to resemble a hellgrammite
Paul, those stomach contents look ripe for Woolly Bugger imitation - just vary the sizes and colors! No wonder Mr. Brown inhaled your fly, looks like you pretty much nailed it. Well done!