|The stinging rose caterpillar, Parasa indetermina.
But they are far from delicious. In fact, you can't even touch them. Their pretty spines can break off and cause an irritating skin rash, a hypersensitive reaction, and other complications serious enough to be called stinging rose caterpillar poisoning.
An attacking bird that gets a painful mouthful of one of these will probably remember the mistake and avoid gaudy caterpillars in the future. Wearing bright colors as a warning about how dangerous you are is called aposematic coloration; it is common among insects.
Stinging rose caterpillars can be found on many familiar woody plants like apple, cottonwood, hickory, dogwood, redbud, sycamore, and on blueberry and rose bushes. The two pictured here were having a meal of bayberry leaves by the side of a road in Cape May, New Jersey.
There is more information about urban insects in my book, Field Guide to Urban Wildlife, which will be published by Stackpole Books in spring 2011.