They are longer than yellow jackets and either yellow and black. In Delaware, the most common hornet is white and black in color. The nests, which can reach basketball size by summer's end, are located in trees, shrubs, and sometimes on buildings. Since the nests grow in size with the season, they often are not discovered until the foliage thins in the fall, well after the hornets are dead. The European hornet, Vespa, the largest of the hornets, usually nests inside tree hollows.
Paper wasps are thin with shiny, dark brown, with brown or yellow markings.
They have long antennae and legs and a pronounced wasp-waist between front and rear portions of the body. These wasps build exposed nests of paper cells under the overhang of buildings, in unused equipment or debris. Occasionally they build in trees or shrubs. They seldom sting unless disturbed and aren't scavengers. Other wasps, such as Cicada killer wasps, spider wasps and parasitic wasps, are beneficial.