The Polistinae are eusocial wasps closely related to the more familiar yellow jackets, but placed in their own subfamily, containing four tribes; with some 1100 species total, it is the second most diverse subfamily within Vespidae, and while most species are tropical or subtropical, they include some of the most frequently encountered large wasps in temperate regions. They are also known as paper wasps, which is a misleading term since other wasps (including yellow jackets) also build nests out of paper, and because some epiponine wasps (e.g., Polybia emaciata) build theirs out of mud,nonetheless, the name "paper wasp" seems to apply mostly, but not exclusively, to the Polistinae, especially the Polistini. Many wasps, such as the Polistes fuscatus, Polistes annularis, and Polistes exclamans, make their nests out of paper. Polistes annularis suspend their paper nests from cliff overhangs via a pedicel, whose free fatty acids induce the necrophoric response in ants and causes them to avoid the pedicel rather than cross and prey on the nest’s inhabitants. Polistes metricus foragers take off from their nests as if they already know how long their trip is. For short flights they exit the nest flying horizontally, while for long flights they exit the nest flying straight up into a high altitude before pursuing their direction. Polistine brood cells are arranged in a hexagonal array, similar to the comb structure in a honey bee nest. At least one epiponine species (Brachygastra mellifica) stores honey in the comb, one of the only insects other than bees to store honey.