Megarhyssa atrata is one of our largest Ichneumons, here are the stats from BugGuide.Net: "Female: body is 38 mm, ovipositor 130 mm, antennae 24 mm." That remarkable ovipositor is used to drill deep into wood and deposit the eggs on the larvae of Siricid wasps such as Horntails.
Not uncommon and often seen flying in woodlands in late spring or early summer, this Giant Ichneumon is hard to photograph because it always seems to be on a mission. This one found a dead tree to its liking and stopped to pose for a couple of pictures.
