The focus is not good on either one of these..but I posted them anyway. If you touch the caterpillar on his back he extends his osmeterium (scent organ) and lets go with a rather horrible odor. I had to endure a lot of it trying to get a decent picture, therefore I'm posting them. This link tells more about it....better pictures too.
http://fireflyforest.net/firefly/200...-caterpillars/