Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Habitat: Riffles
Habitat: Riffles
Diet: For most species, other aquatic insects.
Current speed: Fast
Environmental tolerance: Most species require cool water
Shelter type: No case
A good imitaiton of a Rhyacophila larva is going to catch a lot of trout in swift, bouncing stretches of stream. The same fly is going to do poorly in slow areas of the same stream.
A fly fisherman can avoid wasting time in the wrong sections of a stream by working leap-frog fashion instead of in a straight line. If he is using an imitaiton of a fast-water insect he should fish only the swift, broken currents, skipping past the slower current areas. Likewise, if he is using an imitation of a slow-water insect he should only cover the quieter pools and flats.