Yellowjackets are members of the wasp family. They have a lance-like stinger with small barbs and typically sting repeatedly,though occasionally the stinger becomes lodged and pulls free of the wasp's body. The venom, like most bee or wasp venoms, is primarily only dangerous to those who are allergic, unless a victim receives a large number of stings . Nests are built in trees, shrubs, or in protected places such as inside human-made structures (attics, hollow walls or flooring, in sheds, under porches, and eaves of houses), or in soil cavities, mouse burrows, etc. Nests are made from wood fiber chewed into a paper-like pulp. Yellowjackets' closest relatives, the hornets, closely resemble them but have a much bigger head, seen especially in the large distance from the eyes to the back of the head.