Paper wasps are beneficial because they feed on insects considered pests by humans. They commonly build nests around homes, such as underneath eaves. Wasps attack when the nest is disturbed and each can sting repeatedly; stings typically cause localized pain and swelling, but in sensitive individuals or when many stings occur, more intensive reactions occur, including death.
Paper-like nests, shaped like tiny umbrellas, are suspended by a short stem attached to eaves, window frames, porch ceilings, attic rafters, etc. Each nest consists of a horizontal layer or "tier" of circular comb of hexagonal (six-sided) cells not enclosed by a paper-like envelope. The ends of the cells are open with the heads of the larvae exposed to view." http://umaine.edu/homeowner-ipm/photo-gallery/bees-hornets-wasps/