How do fly fishers differentiate dry flies from wet flies?

Answer 1

Dry flies float using deer hair cut short trapping air between the hairs. Wet flies sink down in the water. Each type of fly is typically used to imitate a particular stage of an insect's life cycle. At the most basic level, a dry fly is one presented so that it floats on the water surface while a wet fly is "presented" to the fish below the water surface.

A dry fly can be designed to float by using a number of techniques. Historically, the materials used to tie the fly would aid in it's buoyancy. For example, some of the hairs on a deer are hollow and can be "tied-in" in such that they aid in suspending the fly. Also, some feathers or furs resist water absorption and can be used to accomplish the same task. Different insect imitations will require different approaches. Modern materials including foam are used alone or in conjunction with traditional methods in the design of new flies. Traditional wet flies are not as commonly used as they were in the past. These flies typically imitated small baitfish patterns or were used to entice a fish into striking. More modern nymph and emerger patterns have been developed which more accurately imitate available food items. When speaking of wet flies, the modern fisherman may be talking about nymph patterns rather than traditional wet patterns.