What is any wasp, let alone this one, doing around here in the later half of October? Most wasps have died out except for their queens who have bedded down for the winter. There are a great many species of wasp and a great many species of ichneumon wasps in particular. What is this one, a giant ichneumon wasp, doing here now?
This giant ichneumon wasp is particularly interesting: it is large; it lives less than a month; it does not sting; the female has a very long ovipositor.
It settles on wood and drives its long ovipositor into the bark and deposits an egg on a horntail wasp. The egg then parasitizes the horntail wasp. 
Very interesting! I didn’t know these are in our neighborhood. Have you ever witnessed the female “driving”’the long ovipositor? My guess is it would be a long process of wiggling it through the bark medium. And how would it know there is a horntail wasp egg there? Sheesh nature is astounding/astonishing!
Nature certainly IS astounding/astonishing! I’d like to meet one of these.