It was nagging at me; what was that black and yellow caterpillar in the Cassia tree? Thank you Florida Butterfly Caterpillars and Their Host Plants for the positive identification: it’s a future Cloudless Sulphur butterfly. This is probably one of the cooler caterpillar varieties. Their diet dictates their color. Mine was obviously feasting on the yellow flowers of the Cassia tree. The leaves would have made him green. Stephanie Sanchez has amazing photos of the contrast on her site, http://butterflies.heuristron.net/.
The photos are fantastic, and Sanchez is a fellow Floridian. Her website is a good resource for identification with over 30 caterpillars and over 40 butterflies represented. This is another one of her photographs of a Cloudless Sulphur butterfly.
Minno, M.C., Butler, J.F. & Hall, W.H. (2005). Florida Butterfly Caterpillars and Their Host Plants. Gainesville: University Press of Florida.