The scalloped oak (Crocallis elinguaria) is a moth of the family Geometridae. It is a common European species. This is a distinctive species, usually with yellow forewings with a broad orange-brown band and a pointed apex. There can be considerable variation, with the central band sometimes the same colour as the rest of the forewing, ranging from pale yellow to orange-brown. Melanic forms are also known. There is always a blackish discal spot on the forewing. The hindwings are plain whitish. The wingspan is 40–46 mm. The adults fly at night in July and August and are attracted to light, sometimes in large numbers.