Stoneflies live relatively short time as adults, compared to their nymphal phase. Some species grow to be bigger than 5 cm. A hand full of salmonflies indicates the massive hatch in the canyon of the Firehole. Trout may have a hard time finding one to eat unless it is trying to crawl to a bank to hatch, or the stonefly nymph gets careless feeding at night. If your imitation is well chosen and your presentation is good, you won't be dissapointed.
They often lose their grip and are taken all year by trout.
Stonefly Life Cycle & Fly Fishing Stonefly Patterns
Some species grow to be bigger than 5 cm. They mate out of the water. Stoneflies are found worldwide, except Antarctica. The Golden Stonefly adults deposit their eggs mostly at dusk or later. Swisher, Doug and Carl Richards.