Thanks, Carie.  I had it narrowed down to the Nolidae, but there are actually 4 spots and the furthest back has a noticeable white line posterior to it.  However, given the variability in organisms of all types, I think three-spotted is close enough.  By the way, sweetgum doesn't grow as far north as Maine, but witch hazel does, which is listed in the Petersen guide as a host. 

Thanks again,
Bruce

On Wed, Oct 8, 2014 at 5:57 PM, Carie Nixon <[log in to unmask]> wrote:
My husband, an entomologist, says:  

________________________________________________

Need to leave or subscribe to the Sciart-L listserv? Follow the instructions at
http://www.gnsi.org/resources/reviews/gnsi-sciart-l-listserv