Help in IDing a caterpillar

[MS LYNN L MONROE]

Hi!

I found a caterpillar on the road today, along the Front Range in Larimer
County, CO, at about 7500'.  When we tried to put it back on the grassy
areas on the side of the road, it was immediately attacked by ants.  We tri
ed another place, and more ants.  So, we decided to try to take it home to
raise it.

Body length is 7/8" (22 mm).  It has a red head with no branched spines and
a creamy-white body with a black dorsal stripe and a black lateral stripe
on either side.  Between the dorsal and the lateral strip on either side is
a row of orange tubercules with orange branched spines (the very tip of the
top spine is black).  Below the lateral black line are two rows of black
tubercules with black branched spines.  The white lateral bands have one
black dot(spiricle?) per segment. Legs are black, prolegs are orange.  It's
quite attractive.

 In Scott's butterfly book it looks most like #195 on page 134, the "body
build" of many Nymphalids.  I've tried a lot of food plants, but so far it
hasn't found what it's looking for.  Any help will be greatly appreciated.
TIA.  Lynn Monroe