Rio's Basic Trout Assortment includes seven of the most popular and important flies for the trout angler. They selected three dry flies representing a mayfly, a stonefly/hopper and a caddis, one soft hackle to imitate an emerging mayfly or caddis, two bead head nymphs for trout feeding on midges, mayflies and caddis, and a bead head bugger that represents minnows or leeches.