Take a look at your Plumeria to see if this colorful caterpillar is munching away at the leaves. This is the georgeous larva of the plain looking tetrio sphinx moth. One of its favorite host plants is Plumeria. Please consider sparing this caterpillar. Your Plumeria leaves will soon be falling off anyway.
Giant Caterpiller Eats Plumeria
For more information see this publication: http://edis.ifas.ufl.edu/in621