This pattern is an imitation of bottom crawling insects that inhabit fast flowing water. These are generally the caddis imitations that crawl about on the stony river or stream bed and are easy prey to hungry trout. They are tied on shaped hooks which gives the basic shape of a caseless caddis. This pattern can either be used as a pair (one on a dropper) or singly on a short leader. Alternatively, it can be used on a longer leader in the traditional nymph method.