Details Great for scuds, midges and shrimp. Very flexible and translucent. Wapsi&';s Sow Scud Back is a dyed, translucent, highly elastic material that is ideal for use on nymphs, scuds, sowbugs, crawfish, caddis, and midge patterns. Sow Scud Back can be used as a wing case, segmented abdomen or wrapped fully over the body of the fly. It is an essential material for tying Czech style nymphs