Northern Prairie Wildlife Research Center
This caterpillar is variable in color (off-white, brown, and grey) and pattern. In fact, the lack of notable features in combination with the presence of mature larvae in early spring serve as the best clue to the identity of this species. It is very common on many broadleaf trees (big-leaf maple and serviceberry) and shrubs (myrica and blueberry) as well as many conifers (pines and Douglas-fir). This caterpillar overwinters and typically occurs from October to April or May of the following year.