The streak (Chesias legatella) is a moth of the family Geometridae. It is found in northern and western Europe and north Africa. It is common in Britain, but local and confined to the north in Ireland. The species is quite variable, the forewings being buff or brown, but is always easily identified by the bold whitish apical streak which gives it its common name. The hindwings are pale grey or buff. The wingspan is 35–38 millimetres (1.4–1.5 in). The moth flies, usually at dusk, in September and October and is sometimes attracted to light.