Moved from Emeralds.

Nice discovery and photo, Tom!

I sent the photo to John Gruber who specializes in this subfamily. His response follows, and has been posted on the species page at MPG:

"At critical pre-emergence temperatures an intermediate green-brown form of Nemoria bistriaria will be induced with brown and green scales sprinkled across the wing in this manner. Nemoria lixaria is rarely seen north of SE Pennsylvania, and its seasonal darker form is melanic with charcoal black scales appearing along the pm. and am. lines and black shading on abdomen and wing fringes rather than the mocha brown form that appears in N. bistriaria. Given the locality and coloration there can be little doubt that this is an intermediate color form of Nemoria bistriaria, probably N. bistriaria siccifolia (in terms of Ferguson's subspecies). Neither N. mimosaria nor N. rubrifrontaria has a known seasonal color variant, and I think those are the only other two Nemoria that might be encountered in that part of Massachusetts."