The last observed of c. two-dozen larvae; and the only  one 
collected and brought indoors (11-September) where it fed on  
Northern Prickly Ash for only two more days before pupating.
Unlike other  late-instar larvae seen, appearing to be smaller, 
this one apparently  skipped the larger last instar, yielding 
this small "Spring form"  adult.  Forewing length, only 47mm.
Room kept at 62°F.  Light from  east & south windows.
Eclosion, 26-Feb-2013.
                                                        D J Hoag, Grand 
Isle, VT