Date notes: I was splitting wood (Oregon white oak) and found 8-10 of these catepillars in rounds as I split them. The rounds were decaying/hollow in the center. I also found acorns in these rounds, probably left by acorn woodpeckers.
Submitted by: db34803
Specimen type: Photograph
Observation notes: outside air temp was ~37 degF. catepillars were very sluggish. The one I brought inside to take pictures became more active as it warmed up. "Head", first body segment with jaws is a molasses brown color, rest of body segments are a washed out green (see pics).
Verified by: davidwdroppers
Verified date: March 31, 2021
Coordinator notes: Unfortunately, there aren't many pictures of the larvae of Cossidae, due to their concealed lives. However, oak is mentioned as a hosts of robiniae, while Acossus populi is mentioned as a more Salicaceae specialist; I find no mention of oak being used by this species. This record should, however, be treated as tentative.