Sticky strips of paper use to capture flies. Adult flies tend to alight on elevated areas where they can obtain a good view of their surroundings. Use of fly paper takes advantage of this behavior; by hanging fly paper from the ceiling or other elevated locations, when flies land they adhere to the sticky paper. The fly paper is often yellow in color, which may provide a visual stimulus for landing, though this is not necessary. Once commonly used in both indoor and outdoor markets, barns, and milking parlors, they largely have been replaced by black-light, electro cuting grid traps where electric power is available.