I may have just found my own answer. Looks like an Imperial Moth caterpillar. Hope he stays away from my garden...looks like he might be able to eat a lot! :)

Here is a link that might be useful: Imperial Moth

The range of the Imperial Moth appears to be largely east of the Mississippi so if you are it may well be. The larva feed on a large variety of trees and shrubs but apparently not to the point of being a pest.

Here is a link that might be useful: Imperial Moths

Yes, it is important that we know the location of a critter when trying to identify it....but in this case, the caterpillar is CLEARLY the Imperial Moth larva.

Thanks to you both. Sorry I didn't indicate my location, which is central Florida on the east coast (Daytona Beach area).

Jo