We’re going in reverse order. About a month ago, I posted pictures of Long-tailed Ichneumenon Wasps. The female was ovipositing deep in a hickory tree. Her target: the larvae of this creature, a Pigeon Horntail, which I saw last week.
The Pigeon Horntail lays her eggs in old wood. This happens to be another hickory, by the way. Couldn’t hang around to see if this was the tree she chose.
The horntail can be seen here, as can the longer ovipositor. Males also have the “horn” or cornus. These creatures may look fearsome, but they do not sting. (So many misperceptions of wasps and bugs in general!) Why “pigeon” though, which is also represented in the binomial?
In addition to laying eggs, this horntail deposits some Cerrina unicolor fungus with her eggs. This is a wood-rotting fungus which breaks down cellulose, helping to make it suitable for the larvae to eat. The predatory Long-tailed Ichneumenon may be able to sense the fungus, which is what leads her to find deeply buried larvae inside trees.
Horntails (and sawflies and wood wasps) are in a suborder of Hymenoptera, Symphyta. The other suborder of Hymenoptera is the Apocrita, which includes the narrow-waisted wasps, ants, and bees (in other words, all the things most people think of when they think of Hymenoptera).
Last year, I saw one of these dead on the side of 4th Avenue here in Brooklyn. This is the first I’ve seen alive.
If you want to leave some nurturing fungi in the wood of this blog….
Backyard and Beyond 
Sorry for the loss of your friend. I’ll keep a good thought for you.
Thank you.