Stonefly Adult
"Early Black
Stonefly"
Adult stoneflies are soft-bodied, elongate insects. The heads have long, slender antenna. The legs have 3 distinct segments. They have membranous/veined wings, often lightly colored, and two tails that are inconspicuous. Unlike mayflies and caddisflies, adult stoneflies can be found throughout the year, some being adapted to winter emergence.
The flight of adult stoneflies is clumsy and lumbering, with 4 wings (2 sets of 2 wings) that make them look pretty big. They kind of "hang in the air" under their wings and look larger in flight than they do at rest. Wings lay folded flat over the back at rest and may extend 10-20% beyond the end of the body.
Some stonefly adults feed, others do not. Some are flightless. Some are wingless. Males generally live only a few days . . . females of the feeding species may live for 4-5 weeks. Males attract females for mating by "drumming" their abdomen and females respond in kind. Mating takes place on vegetation. The female mates only once and lays her eggs in moving water.
Some feel the first recorded artificial fly some 450 years ago was based on a British stonefly. Today, the "Salmonfly" (giant stonefly) of our western rivers, is among the most famous flies. Other popular patterns like the "Golden Stone", "Yellow Sally", "Bird's Stonefly" & "Sofa Pillow" are adult stonefly imitations.
"Giant Salmon
Fly"
