This CDC Yellow Sally has the silhouette that trigger trout to eat
Little Yellow Stonefly or Yellow Sally - Insect Genus Isoperla
The Yellow Sally is in the group of stoneflies that includes over 60 species, which are quite common to many well oxygenated, fast flowing, gravelly bottomed rivers across the U.S., hatching sporadically from May through much of the summer.
Adult Yellow Sally Stonefly: Nymphs crawl onto dry land late in the afternoon, evening and night, where they break out of their exoskeleton to become a flying adult. After mating, the adult female returns to the water to lay eggs, then she dies.
Salmonflies are the only insects that have “in-complete metamorphism.” Meaning that they only have two stages in their life cycle. The first is being a nymph, living in the river or stretch between one and three years. Crawling on the bottom of our freestone streams foraging until the water temperature and timing is right.