Wasp? Fabulous site! Thank you in advance, too! These wasps (?) flew in last night (10/17/05) and swarmed all over just one dying fir tree, they weren’t on any other tree on the property, and they’re gone today. There is a long, 2-3 inches, thin antenna like thing coming out of the back end and they were using it to probe into the cracks of the tree bark.
Willits California , Mendocino County,
This is some species of Ichneumon, a wasp relative. The females use that long ovipositor to deposit eggs deep in the wood. Ichneumons are parasitic wasps and your unidentified species was laying eggs that will devour wood boring larvae that have probably infested the dying tree. Fascinating image.
Eric Eaton’s Correction: (10/20/2005)
“The ichneumon swarm is actually a bunch of braconid wasps. VERY easy to confuse the two, especially in this case because so few braconids are parasitic on wood borers. ”
Update: August 5, 2012
We are trying to clear up some old unidentified postings, and we believe this might be a member of the genus Digonogastra based on this BugGuide image.