Caterpillar Identication

I found this critter in Calais on an old RR track munching on a Balsam poplar. Can’t find it in any of my bug books. Any suggestions?

Can you identify this caterpillar?


  1. Kathryn Kirk says

    The caterpillar in the photo (looking like a lively bird dropping) is a
    butterfly, Limenitis sp. I believe it’s a red-spotted purple,
    L.arthemis) based on habitat but if the RR track is near a wetland, it
    could be a Viceroy, L. archippus. The immatures are quite variable.
    Either way, it’s a nice photo. I refer you to “Caterpillars in the Field
    and Garden” by Allen, Brock and Glassberg published by Oxford U. Press. OR the free USDA publications on Caterpillars of Eastern Forests pg. 94.

    Kathryn Kirk
    Madison, Wisconsin

  2. From Genn and Suzanne It’s one of a variety of bird-dropping caterpillars. 😛

  3. Submitted on 2012/05/25 at 10:35 am
    I think Fred’s caterpillar is a Viceroy or White Admiral. Both species have quite variable caterpillars and some lepidopterists think you can only be sure by rearing them to adulthood. Both species eat poplar.

    See this photo viceroy

    and this info: viceroy admiral complex

    white admiral:

    Hope this helps,

  4. Tiger swallowtail