Northern Prairie Wildlife Research Center
This is one of many caterpillars that exhibits more than one color phase, either by stage of development, genetic polymorphism, or other environmental factors. Color phases differ according to age. Early instar: Mid abdominal segments with middorsal clusters of red hairs among bright yellow hairs; anterior and posterior with long wisps of white hairs and shorter yellow and black hairs. This caterpillar is very common on many broadleaf trees such as big-leaf maple and red alder, during July and August.