A size 8 fly that imitates the nymph of the Large Stonefly.  The body is yellow-beige dubbing, the legs and antenna are barred rubber and the eyes are gold dumbbells.  This fly fishes upside down, so the raffia wing cases are on the underside of the hook.  Due to its upside down style hook ups on the riverbed are rare.  Fish this fly in a dead drift manner on fast rivers with stony or rocky bottoms.  This pattern can be used on lakes with stony shores, but rainbows will take it readily even when the naturals are absent.  Mid-April to the end of June is the most productive time on rivers.