I saw this unusual bug lurking on the office door window just this past Saturday. A bit of research indicates it is an ailanthus webworm moth. Native to South Florida down to Costa Rica, these moths have migrated as far north as southern Ontario. I have not seen too many around here. This upper picture taken inside the office, and the picture below (with the shadows, reflections and refractions) taken from the outside.
This moth does not survive the colder winters but does have a lifespan of about four months. I saw this one in July so he has a chance to make it the full four before the coldest weather sets in here!