This familiar, strong-flying species is our largest white butterfly (2), and is often an unwelcome visitor to gardens because the caterpillars damage cabbages and other realated crops (2). Females are distinguished by two black spots and a black streak on the fore-wings (1). In both males and females, the undersides of the wings are yellowish with black flecking (1). The caterpillar grows up to 4 cm in length, and is generally pale green with black spots, with a yellow line along the back and one along each side (3).