Wasps of the cosmopolitan genus Polistes (the only genus in the tribe Polistini) are the most familiar of the polistine wasps, an are the most common type of paper wasp. It is also the single largest genus within the family Vespidae, with over 300 recognized species and subspecies. Their innate preferences for nest-building sites leads them to commonly build nests on human habitation, where they can be very unwelcome; although generally non-aggressive, they can be provoked into defending their nests. All species are predatory, and they may consume large numbers of caterpillars, in which respect they are generally considered quite beneficial. The European paper wasp, Polistes dominulus, was introduced into the US about 1981 and has quickly spread throughout most of the country, in most cases replacing native species within a couple of years. This species is very commonly mistaken for a yellowjacket, as it is black strongly marked with yellow, and quite different from the native North American species of Polistes. Polistes can be identified by their characteristic flight; their long legs dangle below their body, which is also more slender than a yellowjacket.