Common often abundant, especially in autumn, in a wide variety of habitats, including gardens, woodland, heathland and marshes throughout the British Isles. Widespread and extremely common in Hampshire and on the Isle of Wight. Wingspan 35-45 mm. One of the most frequent visitors to light traps in autumn and very easily recognised, the most likely confusion species is Double Square-spot X. triangulum
. Larva feeds on a wide variety on herbaceous plants, including Stinging Nettle, White Dead-nettle, Great Willowherb, Rosebay Willowherb and Greater Burdock.