A Cabbage White Butterfly has mostly white wings, but is also has some black edging and small dots. Like all butterflies, it is in the order of Lepidoptera. It's larvae, green catapillers, do a lot of damage to plants in the Brassicaceae family-cabbage, chard, kale, etc. They are fairly common in the US, imported here accidentally. Birds and other predators won't eat them because they taste bad. They are also known as the "small cabbage white". The "large" species or sub-species is found in Britain and having black streaked larvae.