A White-marked Tussock Moth Caterpillar (Orgyia leucostigma) feeding on a Rugosa Rose (Rosa Rugosa) at Distant Hill Gardens. It looks a bit like a toothbrush, but I don't recommend using it as one. Contact with the poisonous hairs or spines of the White-marked tussock moth caterpillar can cause skin rashes.
FYI - The color of the tufts may vary from white to yellow.
For more info on this interesting family of insects, the Tussock Moths, visit my blog: