Currently viewing the category: "Horntails, Wood Wasps and Sawflies"
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Horntail or not?
My mother and her friend at work, caught this after much hysteria (apparently) thinking it was a wasp. We’re in Norfolk in the UK and it looks like, on your site, someone else has found one in the same area. It is about 3 – 4 inches long. Is it a Horntail? I’ve looked around the web and the pictures I’ve found of Horntails have different coloured eyes and abdomens to this, although they share a lot of other similarities. Also any idea whether it would sting? Thanks in advance!
Stuart Millins

Hi Stuart,
This is virtually identical to the insect we received two days ago that we identified as a Horntail. One of our American Species, the Pigeon Horntail, Tremex columba, looks very similar except for the coloration. They do not sting. The female uses the stingerlike ovipositor to deposit eggs under the bark of trees where the young larvae bore into the wood. A websearch of Tremex and Britain might turn up a photo. Please let us know.

Ed. Note: Additional searching turned up information on the Great Wood Wasp, Uroceras gigas as well as this illustration, which seems to positively identify this British Horntail.

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What is this?
Dear WTB,
please help me identify this bug, we live in Norfolk in the UK and it landed in our garden, on a hot sunny day this July. The only thing I have found that is similar is a ‘Hornet Robber Fly’ but it has a different body and yellow eyes. > I look forward to hearing what you think it might be!
Matthew Johnson

Hi Matthew,
We are unfamiliar with the English species, but this bears an uncanny resemblance to a Horntail, a type of wasplike insect in the Family Siricidae. They have cylindrical bodies with the thorax and abdomen broadly joined together, not separated by a waist. In females there is a stinger like ovipositor which is used to drill into stems or wood where eggs are laid. Adults feed on nectar.

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what is it?
WHAT IS THIS???!!!….I heard a buzzing in the trees and found this bug. It was so big and lethargic that it could not fly. I would say it was at least 2 inches long. It moved very slowly and it looked like it was dying. When it was still on the leaf it’s whole body would expand and contract..very yucky..I live in BC Canada..this is the second time I have seen a bug like this in my yard. I did a search on wasps and flys, but I couldn’t find anything that resembled this. Hope you can help!!

Hi Jen,
We consulted with Eric Eaton to try to get a species name for you, but he arrived at the same generalization we did. This is a Cimbex Sawfly. These are non-stinging relatives of wasps. The larva feed on the leaves of trees, especially willow. Sawflies can be recognized by their club-shaped antennae.

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Mystery Bug
Can you identify this bug for me, please? Looks like a stonefly, but the head seems to large, the prothorax to small, and no tails. I’m really stumped!

Hi Roger,
We wanted to be sure, so we contacted Eric Eaton. Here is what he has to say: "The image you sent is actually of a sawfly, but I see the resemblance [to a stonefly]! Without knowing more information, I can’t even tell you which sawfly family this belongs in. However, this is the time of year when sawflies are in greatest abundance here in the U.S. and in Canada.
Sawflies are related to ants, bees and wasps, belonging to the order Hymenoptera. Larva of most species feed on foilage. They do not sting.

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Cicada Killer? Photos included
We saw this wasp in Vermont on a camping trip in August 2004. It appeared on a large rock. For whatever reason, it did not fly. It was very slow moving, and it stayed in the same spot for a few days. "Cicada Killer" is the first thing that came to mind, but when i got home and looked on the internet I could not find a matching photo. This specimen has white markings, not yellow. It’s thorax and head are black, not brownish. And the legs and antennae are yellow and black. This was the largest wasp/hornet i’ve ever seen. I would say it was close to 2 inches. Can you shed some light as to it’s identity? Thank you for your time.
– Mike V.

Hi Mike,
We wrote to Eric Eaton and he just responded: “My chief suspect is a cimbicid sawfly, Cimbex americana, family Cimbicidae. Behavior fits, as they are slow-moving. They can approach an inch in size, but do not sting. Can bite, though.” Two inches seems rather large and possibly not entirely accurate.

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Can you help me ID this caterpillar found on a trail in the mulch, in southern Ohio?
Caesar Creek Lake

Hi Kim,
Thanks for the Sawfly larvae photo with, I assume, your fingers for scale. Sawflies are not flies, but members of the Hymenoptera which includes Ants, Bees, Wasps, Ichneumons and many other families. We checked with Eric Eaton, an entomologist who believes it is one of the Cimbex species because of the large size. Cimbex americana is usually listed as our largest American sawfly, and the adult somewhat resembles a bumblebee. There are several color varieties as well. The larvae are described as yellow-green, but with the distinct black stripe down the back. Your photo could be a color variation of Cimbex americana or a closely related species. The caterpillar-like larvae feed on the leaves of a variety of trees. They can spurt a fluid when disturbed. The fullgrown larvae then crawls to the ground, where you found them, and find a place to burrow where they make a brownish cocoon to spend the winter. Thank you for adding to our site with a brand new page. We love getting new species.

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