Currently viewing the category: "Horntails, Wood Wasps and Sawflies"

Caterpillar identification (hopefuilly!)
I was digging around hoping that I could ID these guys. I am in upstate, NY (finger lakes) and this was taken Sept 13, 2005. They were happily munching on some Pignut Hickory leaves until I disturbed them, and then their butts went up in the air. I tried touching them with a stick, and they have an amazingly strong ability to push on the stick and act quite aggressively. I have never seen these before, and am hoping for an ID. Thinking of going back there and gathering a couple to wee what they become. Probably a dull, grey moth.
Mark Wyman

Hi Mark,
Sorry for the delay. This one was tough. These are not caterpillars, but the larva of a wasp relative known as a Sawfly. We actually found it while researching a spider wasp after our caterpillar searching turned up nothing. It appears to be Croesus latitarsus, or something very closely related. We located a link on BugGuide that says they raise their bodies to defend themselves.

Any idea what the heck this is?
Good evening.
Well I went out tonight to cut down two dead maple trees and that’s when I saw them. Unfortunately they are dead, I thought maybe they were wasps (as we have had problem with them lately) but after the deathly spraying I noticed they looked like nothing I had ever seen. The protruding black, well let’s call it a tail, was sticking in the tree?

Hi Chris,
These are Pigeon Horntails, Tremex columba, and they are wasp relatives, but do not sting. The portruding tail is a female’s ovipositor, and she uses it to deposit eggs under bark so the wood boring larvae will have a food source. We have heard reports that sometimes she gets stuck and dies attached to the tree, and your letter substantiates that.

Dear Bugman,
You have a great site. Wish I had found it years ago… I live in eastern Colorado and have never seen wasps like this before. I found two, very large wasps(?) on the ground at the base of a dead tree. One flew off, slowly circled and landed on the same tree and began crawling down, dragging and jabbing it’s "tail/stinger" along the bark. Is it laying eggs? Searching out insects? The other wasp was dead- It has a body length of 1 3/8" (it was the smaller of the two wasps) with 1/4" antenna and tail/stinger. It has the yellow and black stripes on its abdomen. It doesn’t have the common thin wasp waist. I hope you can tell me what these are? It was great fun to watch and photograph. Thank you so much for your time and attention,

Hi CC,
This is a Horntail in the Family Siricidae. The most commonly depicted species is the Pigeon Horntail, Tremex columba, but your specimen is marked differently. We are relatively sure it is the genus Tremex, but are unsure of the species. Horntails are related to wasps but do not sting. That stinger-like ovipositor is used to deposit eggs under bark so the wood boring larvae will have a food source.

Ed. Note: We later contacted Eric Eaton who wrote back: “It IS Tremex columba. The book “Bagging Big Bugs” lists it for the Rocky Mountain states, and the image in there matches yours perfectly. “

Pigeon Horntail
I found a bug on your site I could not ID. THANK YOU! Interesting enough, you have indicated that it’s found in forests of the Northeast. This guy was photographed on the sidewalk in front of my house in Round Lake, Illinois (far Northeast corner). It’s not the first time I have seen this species but was the first time I had a camera available. Here are two views.
Thanks for the great web site!
Robert Fesus
Buffalo Grove, Illinois

Hi Robert,
We just love it when people look at our site for research and identification. Thanks for the images. When we first posted stories about Pigeon Horntails, we could only locate one image on the web, which we pilfered. Thankfully, we now have several sent to us directly.

Mystery Bug
This bug drilled a perfect hole in the ceiling of our newly refinished basement, any ideas? It was found dead under the hole covered in sheetrock dust. Any clues to solve this mystery would be appreciated.
Greg Martin

Hi Greg,
Your Horntail species did not drill a hole into the ceiling, but rather bored out of the ceiling. The larvae are wood borers. Our guess is the wood used in the refinishing was infested, hopefully with a single larva, and when it matured, it drilled its way out.

bugin me
can you ID this one please ?

Hi Jeff,
We have been waiting for years for a photo of a Pigeon Horntail, Tremex columba, a relative of wasps and sawflies. It is found in hardwood forests of Eastern North America. The female, like your specimen, uses her ovipositor, which looks like a stinger, to deposit eggs into wood. The larvae eat fungus infected wood of elm, beech, maple, oak and other deciduous trees. The larvae live for about two years inside the wood and they often become prey to Giant Ichneumons.