Foraging habitats as well as the tluctuations in vespid species' abundance in Mato Grosso State, Brazil, were deterrnined,t hrough sampling effon per hour per collector in four cerrado sensu lato habitats," campo úmido" (Cu)," campo sujo" (es), "cerrado sensu stricto" (Css), and "gallery forest" (Mg), during four periods consisting of two dry (August 1988 and June 1989) and two wet (October and December 1988) season periods. For "campo úmido", sorne species seern to be highly seasonal, either in the dry or wet seasons, whereas very few species occur year-round. The abundance, species composition and richness varied between habitats types and between seasonsForaging habitats as well as the tluctuations in vespid species' abundance in Mato Grosso State, Brazil, were deterrnined,t hrough sampling effon per hour per collector in four cerrado sensu lato habitats," campo úmido" (Cu)," campo sujo" (es), "cerrado sensu stricto" (Css), and "gallery forest" (Mg), during four periods consisting of two dry (August 1988 and June 1989) and two wet (October and December 1988) season periods. For "campo úmido", sorne species seern to be highly seasonal, either in the dry or wet seasons, whereas very few species occur year-round. The abundance, species composition and richness varied between habitats types and between seasons