Caterpillar Identification Please

[Jenna Ogilvie]

I have found a caterpillar that I don't recognize and is not in my audubon
society field guide to butterflies.  I live in Knoxville, TN and there were
3 on a parsley plant.  The  larger 2 caterpillars are about 2 cm in length
and are black with tiny red spines and a white stripe over the middle of
their backs.  The smaller one is brownish with a white stripe and looks as
though it will develop the black and red colors as it grows.  Does anyone
know what type of caterpillar these are?  Many thanks,
Jenna Ogilvie
dramaduck at hotmail.com