The last two in the project were flies pretending to be wasps. Hard for this one to pretend to be anything but what it is--the largest wasp in the northeast, or at least the longest. That thread protruding from her abdomen is her ovipositor, and it brings her length to about four inches. This is the giant ichneumon Megarhyssa macrurus. She'll stab that thing into a rotting stump right into the body of a pigeon horntail larva and deposit her egg. Her baby then feeds on the horntail baby and, as they say, the beautiful cycle of life continues.
Despite her warning coloration and her terrifying (to many people) appearance, the giant ichneumon is not at all harmful to humans.