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.
This is the first of it's family I've seen, collected from a tiny, fishless stream in the Cascades. The three species of this genus all live in the Northwest and are predators that primarily eat stonefly nymphs Merritt R.W., Cummins, K.W., and Berg, M.B. (2019).
Crustaceans are classified as one of those inconvenient intermediate taxonomic levels, the subphylum. The varieties of interest to trout anglers are in the class Malacostraca.
It contains the orders of scuds (Amphipoda), sowbugs (Isopoda), opossum or mysis shrimp (Mysida), and crayish (Decapoda). Crayfish and scuds are both extremely important trout prey.
I decided not to include all the sub-this and infra-that taxonomic levels on this site and stick to the ones covered in high school biology, because it makes the navigation much easier and it's sufficient for anglers' purposes.
For the rare cases in which some well-known taxon falls on a more obscure level (like crustaceans, damselflies, and dragonflies), I've appended or prepended it to the listed taxon with a hyphen and explained the details in the corresponding description. It's not the most graceful system but it works.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist