This was photographed on a large silver maple in Beechwood Cemetery. Oddly, there were five of these female horntails on this tree, all of them dead, all still with their ovipositor stuck in the tree trunk. I have no idea why. However, these large members of the Hymenoptera (about 25mm) are interesting insects, for when the females lay their eggs, they also inject a fungus from their abdomen into the tree, to help soften the wood further, for their larvae to burrow more easily through it. They ONLY lay their eggs in trees already dying or almost dead, not in healthy living trees. Their larvae are preyed upon by the spectacular Megarhyssa wasp.

These wasps DO NOT sting and they are harmless to people! In this photo you can see the slender ovipositor stuck in the tree. The larger protrusion is the sheath for the ovipositor.