The wings are white or buff with a network of brown lines (hence its common name). These lines vary in thickness and sometimes the wings are almost entirely dark brown. One or two broods are produced each year and the adults can be seen at any time from May to September . This species flies during the day but also at night and is attracted to light.
The larva is green with white lines and feeds on bedstraws and various legumes such as clovers, lucerne and meadow vetchling. The species overwinters as a pupa.