A new species, Chaoborus sampsera, is described from male and female adults collected from Papua Province in western New Guinea, Indonesia. Based on leg banding, wing pigmentation, and possession of a median paramere sclerite in males, the new species belongs to the Chaoborus “pallidus” group of Colless. Chaoborus sampsera is distinguished from other species of the “pallidus” group by the scimitar-shaped parameres. Although relationships among these Chaoborus species are unclear, there are morphological characters that support the “pallidus” group.