If Caddis are the potatoes and the Mayflies the vegetables, then Stoneflies are Prime Rib. It's hard to not enjoy fishing a big bushy dry fly and have trout rise and inhale it like an alligator on a zebra at the waters edge. In California, our Stonefly hatch begins as early as April, and peaks in May and June. Farther east, in the Rockies, these bugs pop out as late as July or August. When you've timed a trip that hits this hatch, it will be more than the trout that will be hooked.