Large black caterpillar, cocoon, moth - Los Angeles
Based on the image of the moth, I think this is a Painted Tiger Moth (Arachnis picta). See the image of the moth from the Wikipedia (you can even see the yellow color at the head region):



An image of the caterpillar can be found here, but this is less decisive.
It also fits with the geographic location where you found the moth, see here.