American Dagger Moth Caterpillar

I was greeted by this fella crawling up the siding on my house...probably looking for a crevice in which to pupate. This is the caterpillar of the Dagger Moth (Acronicta americana) and is one of the touch-me-nots of the Lepidopteran world. Those stiff black "hairs", if touched, will break off and work their way into the skin and inject a toxin that will be reminiscent of a bee sting and, over time, a bad rash will develop. That bright yellow color is Ma Nature's way of warning you not to mess with this bad boy. 

Extras: I have included a photo of the adult (in case you were wondering) which I have borrowed from a Google search. Photo credit was not included on the site.