'Forest Pansy' redbud at our office had some serious munch marks. I flipped over the leaves and, lo and behold, there were several io moth caterpillars hiding out.
I just love the color of these caterpillars--almost an electric lemon-lime color--so I like to get close and really admire them. But it's best not to touch--they have stinging spines on their bodies (see the tufts?), so it's a good idea not to touch them.
Caterpillars typically go through several stages before pupating and turning into moths or butterflies. These caterpillars are probably first instars, based on their markings. In time, they'll develop into io moths.