Hi Jim.
   No need to apologize for questions about butterflies.  Many birders
part-time in butterfly surveys - and are actually duel birders.
   The caterpillars that you mention on milkweed, however, most 
likely belong to the Milkweed Tussock Caterpillar Moth.
   The female lays rafts of eggs that hatch into densly hairy, and
beautiful, caterpillars with orange and yellow tufts.
   Hope this helps.
 Lance
BTW, the adult moth of this species is much rarer than its
caterpillars!