You didn't find it under butterfly larvae because it's the caterpillar of a moth, Euchaetes egle....also called the Milkweed Tussock caterpillar.

Many, if not most, tussock caterpillars have stinging cells on their backs, but I do not know if this one does. I'm always wary about picking up really fuzzy individuals and would use gloves.

Birds won't eat this guy, by the way, so don't bother tossing them in the direction of the nearest bird bath.

Thanks. Was hoping the mass of these were butterflies.