Here on the Au Sable when the May heat comes Stone Flies start hatching! Most of them crawl out of the river to emerge but then come back to lay eggs and are floating/crawling down river. Huge food source for our brown trout and great pattern for the night time anglers. Mostly you see larger stones fished as a searching fly while floating down river and then packed away when the Mayflies appear. They sure can produce a random heavy feed during a non feeding time. Evening time is when stones start coming back to river and after dark. Very productive when trout are feeding and mayflies are on the water in low light. Many trout are very selective in what they eat during heavy hatches and spinner falls. Many gobble up a stone fly!!
Last year during Hex Hatch here was a beautiful Brown caught on a golden stone in the evening hours!
I have added a few of my most popular Stone Fly patterns to our online sales and more will be coming!
https://michigan-streamside.com/product-category/flies/dry-flies/stone-flies