bristly black caterpillar?

[Dr. James Adams]

Dear John K. and listers,

In response to your listing:

> Amid wooly bear season I came across a
> large black bristly caterpillar I haven't seen
> before. Even, stiff black bristles all over
> except for some hairless red "bars" on top of
> it's back. 2-3" long, same habitat as the wooly
> bears (at least, I found it curled up
> roadside...just in time!).

You definitely have Hypercompe (formerly Ecpantheria) scribonia, also 
known as the Leopard Moth.  This moth is in the family Arctiidae 
(Tiger Moths).

 > Any ideas? What does it eat? how does it
> pupate? Thanks in advance. You've all been
> very helpful before. I'd like to keep it until
> pupation but it needs to eat constantly so I may
> release it later today.

Sorry I didn't get back to you very quickly.  The caterpillar is very 
likely trying to diapause, and, although it may eat some more, it 
probably doesn't need any more currently.  If you want to try to feed 
it something, dandelion, plantain, or any of a number of other 
"weedy" plants should work.  This species overwinters as a final 
instar larva, and you could probably keep it in an open container 
with significant topography (dirt, leaves, hollowed out sticks/bark, 
etc.) outside in a protected area over the winter.  When temperatures 
get warm enough in the spring, the larva will become active again, 
eat just a little bit, and pupate in the leaf litter.  The adult 
should emerge in May/June.

HOpe this helps and is not too late.

James Adams