Both anglers and entomologists know these diminutive flies as "Microcaddisflies." The term refers to this family specifically, not to all tiny caddisflies. Many are large enough for imitation on small hooks, but some are impossibly small, as tiny as hook size 36.
Like the Tricorythodes mayflies, Microcaddisflies can be important to trout because of their extreme abundance in certian waters.
I'm tentatively classifying this one as Dibusa angata because I cannot see any ocelli in my dorsal view of the head (and because it has a single spur on each front tibia). However, sometimes they can be difficult to spot when obscured behind setae in general, so I'm not 100 % sure on this one. If there are ocelli I missed, then based on ranges and colors the genus ought to be Stactobiella.