Larvae id for a friend!!

[Sheri Moreau]

Hey, everyone! Thanks so much for helping me id the tussock moth (well,
shucks, I knew it was a tussock larvae, duh!!) species in my previous id
request! Just got this email from a friend; perhaps someone could help him
out. You can email Mark directly at <herdering at pobox.com>. I'm sending him
info on how to join Leps and Dplex!

TIA, Sheri

-------------snipped from Mark Herdering's email-------------
Yesterday I took a stroll through the Sepulveda Dam Basin (Ed. note: Los
Angeles area) hoping to find some milkweed and hopefullly some Monarch
caterpillars. Didn't see any milkweed but I'm betting its there because the
Monarch butterflies were
everywhere.

My copy of Petersons First Guide to Caterpillars is on order and won't be
here for another week and I found a caterpillar I've never seen before.
Along the path I was
walking I came upon a thick growth of a plant who's leaves look very
similar to our narrow leaf milkweed but it was already about 3 to 4 feet
tall and it grew straight up like gopher purge. On these plants were
caterpillars that are quite large. Their bodies are very similar to a
Sphinx moth larva (like the tomato worms we get) with a large, smooth body
and a horn on the rear. However, each caterpillar looked very different
dpending upon its stage of development, much like the Anise Swallowtail.
The smaller ones are very dark, some just black. The largest is mostly
green with yellow and orange stripes running down its body with lots of
black on its back. Its tail and feet are orange and its head is green.

Other than the color scheme, it looks just like a tomato worm. Any ideas
about it might be?
---------------unsnipped---------------------------