This large caterpillar was munching away on the leaves of wild parsnip (Pastinaca sativa). At the moment, the public has discovered this plant, thanks to the hysteria surrounding Giant Hogweed, and the news that this plant too can cause skin blistering. I hope some well-meaning soul does not come along and whack down this and other of the parsnip plants at the garden. They are always well used by a huge variety of nectaring insects and as can be seen, are always host to the caterpillars of the spectacular black swallowtail.