Is this some kind of stump stabber?
Location: Burnaby, BC, Canada
August 24, 2011 5:17 pm
Hi, I was washing my car today and found this resting in one of the doors. It is just over an inch long, black with yellow highlights on legs, head and antennae, and two rather long pointy extension on its abdomen. One located above the other and about half as long as the other. I have never seen an insect like this and would like to know what it is and where it is from. Thanks.
Signature: – John D. Williams


Dear John,
Indulge us if we go off on a tangent prior to responding to your questions.  You had us at your lead with the tantalizing question regarding a Stump Stabber.  We have a vague recollection of hearing the name in the hazy past, but at any rate, it immediately conjured up a picture in our minds of a Giant Ichneumon, a somewhat unwieldy common name for
Megarhyssa atrata, and her close relatives.  One would never call the male Giant Ichneumon a Stump Stabber, as he lacks the 5 inch long ovipositor the female uses to lay eggs that hatch into larvae that feed on the wood boring larvae of the Pigeon Horntail, a type of Wood Wasp.  

So, we looked up the name Stump Stabber and we found the Canadian Talk About Wildlife website and sure enough, a Stump Stabber was pictured to be a Megarhyssa, possibly Megarhyssa macrurus.

Your Hymenopteran, Urocerus albicornus, is a Horntail Wasp that lays her eggs in “hosts include fir, larch, spruce, pine, Douglas-fir, hemlock, and western red cedar” according to BugGuide.

Hi Daniel,
Thanks for the info. I got the term Stump Stabber from a bug field guide I got as a kid, “Bugs of British Columbia, a Lone Pine Field Guide by John Acorn and Ian Sheldon”. I just thought it was that kind of bug because of the ovipositor and the long hind legs. I got a better picture of it when I let it go onto a plant. It is attached if you’re interested.
Thanks again,
John Williams

Horntail: Urocerus albicornus

Thanks for sending us a new photo of this elegantly beautiful Wood Wasp that clearly shows her ovipositor.

Location: Canada

Leave a Reply

Your email address will not be published. Required fields are marked *