The common swift (Korscheltellus lupulina) is a moth of the family Hepialidae. It was previously placed in the genus Hepialus. It is a common, often abundant European species. The male has a wingspan of about 30 mm with dark brown forewings with white apical and basal streaks meeting to make a 'v' shape with another spot close to the costa. The hindwings are plain brown. The female is larger (wingspan about 40 mm) with similar patterning to the male but generally paler and less distinct. A significant proportion of individuals of both sexes are plain buff or brown with no pattern. The adults fly from May to July and are attracted to light. The species overwinters as a larva.