Wet flies imitate insect features and natural movements of aquatic insects and can also mimic larger creatures found in streams and rivers. They can emulate everything from the "swimming" movements of mayflies and caddisflies or scurry like crayfish and minnows. The state of the art in wet fly patterns toward the end of the 19th century displayed stiff and colorful feathered, winged patterns - artful salmon wet fly patterns come to mind. Soft-hackled flies with sparsely tied spider-like bodies are highly effective in catching trout and grayling as they swim more naturally in the water. These flies give the impression of legs, wings, and shucks of various insects such as mayfly emergers, duns, spinners, gnats, midges, and other nymphs. The pulsating hackle and air bubbles trapped in the soft material create a lifelike appearance. They can be fished at different levels in the water column to increase their effectiveness. The presence of a soft hackle wrapped around the neck of the hook or a feather wing differentiates a wet fly from a nymph. Soft hackle wet flies can mimic mayflies and caddis pupa swimming towards the surface. They often drown in the surface film, or they drown when they hit the turbulent water at the back side of gravel bars. Trout focus on emerging, crippled, and drowned insects. Wet fly fishing takes advantage of all three.