I very rarely fish stonefly patterns. But sometimes they can appear in large numbers. If you experience this,you will most likely have a great time fishing. They take to the water to drink. The Dinocras Cephalotes is the largest stonefly here in Scandinavia.
This pattern originates from Staffan Lindstrøm,and it is essential when fishing the great river Rena here in Norway. These are quite large insects and the fish will not let this meal pass. I use Staffans 123 yarn for the body,a mix of organza and antron yarn for the wings. Then use a paper clip and mix a few colors of cdc to create the head and legs on the imitation.