Melanchra picta 
  
The adult moth seems to have no widely used common name, but the caterpillar 
  is the well known Zebra Caterpillar. I have found them feeding in large numbers 
  on Amaranthus and Rumex, though when full grown they demanded 
  a change of diet and seemed satisfied when I offered them willow. After pupation, 
  some moths emerged in the same year; others waited until the following spring.