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.
I have never seen this name used in the scientific literature or in books for anglers, but apparently—at least for kids—the common name "periwinkle" is sometimes used to refer to cased caddisfly larvae.
This common name refers to only one order. Click its scientific name to learn more.