Giant ichneumon wasp

7070.          Wondering what this Insect is, I thought it was an immature dragonfly, there are about 50 on this dying tree. Are they harmful? Do I just leave them alone? Turkey Point, Ontario. Canada

Number 7070. This is a giant ichneumon wasp, Hymenoptera: Ichneumonidae, in the genus Megarhyssa; likely M. macrurus. It is a female in the act of boring through the tree wood in order to lay her egg in the tunnel of her prey, the larva of a wood wasp in the family Siricidae. They are harmless to humans as well as to the tree. Click here for details on their life history.