A female giant wood wasp lays her eggs in the trunk of a tree. She frequently chooses a tall conifer such as a larch or fir. Using her long, pointed ovipositor, she perforates the wood and deposits her eggs inside. The larvae take up to three years to mature, and the trees in which they live may be sawn into planks and used as building materials while they are still inside. Once mature, male giant wood wasps may reach 1 .2 in. in length; females can reach up to 1 .6 in.