Caterpillar ID

[Jenna Ogilvie]

Hi!  I live in East Tennessee (Knoxville), and a few minutes ago I found a
cute little critter on a tulip  poplar tree in my backyard.  It has a kinda
oddly proportioned head compared to the rest of its body.  Its head is
large and yellow.  The body is pale yellow with a purplish black stripe
down the length.  I looked in my Audubon Society field guides for
butterflies and for insects, but I couldn't find it.  The closest thing was
a skipper caterpillar, which was only similar in shape, but not coloration.
 Let me know if anyone has a clue what it is.  Thanks in advance.  :)

Jenna