What To Do If Ichneumon Wasp Stings? Helpful Tips

While ichneumon wasps usually do not sting humans, it’s not a bad idea to be prepared. Here’s what to do if ichneumon wasp stings and why it isn’t a big deal.

Scared of the giant ichneumon wasps buzzing around your garden? I can’t blame you for fearing wasps, for they do have an ill reputation for their painful stings.

However, should you be afraid of ichneumon wasps? Will it cause you any kind of infection or disease? What should you do if you get stung by one? Let’s figure it out.

Can Ichneumon Wasp Sting?

The huge stingers of the ichneumon wasps might indeed be scary. Adult wasps of these species have stingers up to four inches long, which are hard and powerful enough to drill into tree trunks. However, only a few varieties of ichneumon wasps sting humans at all.

Unlike many other aggressive species of wasps, ichneumon wasps usually keep to themselves and aren’t bothered by the presence of humans. Even the giant ichneumon wasps are harmless to humans unless you go ahead and disturb them first.

Are These Wasps Harmful to People in Any Way?

You do not have to worry about the ichneumon wasps at all; they aren’t harmful to humans in any way. As mentioned earlier, only some of them are stinging wasps, and even those don’t usually sting humans except in self-defense.

Rather, these wasps are very beneficial for your garden, acting as natural predators of pests that can harm your plants.

Being parasitoids, ichneumon wasps use the larvae of other pests to lay their eggs. A female ichneumon wasp injects its eggs into a larva, where the egg hatches.

The newly hatched wasp larva starts feeding on the fluids and fats of the host larva, eventually killing it. This helps keep other pest populations under control.

Can They Inject Their Eggs Into Humans?

So that last bit was a bit scary, right? Can female wasps lay their eggs by injecting them into humans too?

It might evoke flashbacks of the movie “Alien.” A wasp larva growing and feeding inside your body is indeed a terrifying thought. However, rest assured that ichneumon wasps cannot and do not inject their eggs into humans.

These wasps prefer small insects, or more specifically, insect larvae, as hosts for their eggs. Common host species include tomato hornworms, horntails, butterflies, etc.

This is because, along with the eggs, they also inject venom that suppresses the immune system of the host. This venom isn’t strong enough to work on humans, so if they try to inject their eggs into your body, your immune system will simply fight off the venom and kill the eggs.

What Should You Do if One Stings You?

While it’s unlikely that you will ever get stung by an ichneumon wasp, if it happens, you should be prepared for it.

In case you accidentally end up mishandling or provoking them in any way, they might get aggressive and sting you.

The venom of an ichneumon wasp can cause serious symptoms but mostly if you are allergic to it. Here’s what you should do, depending on the severity:

Serious symptoms

Serious symptoms may include loss of consciousness, tightness of the throat, hoarseness, dizziness, swelling in areas other than where the wasp stung, cramps, etc.

In case of such severe symptoms, call the emergency helpline for medical attention. If you have epinephrine available, inject a shot of it immediately. Here are a few things to keep in mind:

• Don’t take more than two shots of epinephrine except under medical supervision. You should take the second shot only if the first doesn’t deliver results within 10-15 minutes.
• Avoid injecting it into your hands or feet, as doing so may result in tissue damage. The best place to inject epinephrine is the thigh.
• Even if the injection works and the symptoms are gone, you still need to visit the ER.

Those who have a history of severe allergic reactions should take the epinephrine shot without waiting for any symptoms to appear.

Don’t worry; it won’t cause any harm. However, if your doctor has prescribed a specific anaphylaxis action plan, you should follow that instead.

Non-serious symptoms

Non-serious symptoms include sharp pain, itching, burning, or swelling at the sting site.

As long as you don’t have a history of allergic reactions and the symptoms aren’t severe, you don’t need emergency medical attention.

Just follow the steps below to get rid of the stinger and treat the wound:

• Firstly, you need to remove the stinger in case it breaks off and got left behind. Just scrape the area with a straight object, like a credit card, to push out the stinger. Make sure not to pinch the stinger, as it can release more venom.
• Now that you have gotten rid of the stinger apply ice to the area. It will control the swelling and the pain. Also, if you are wearing any tight-fitting jewelry in the stung area, remove them before it becomes impossible due to the swelling.
• If the wasp stung your hand or leg, elevating it will help limit the swelling, too, by reducing blood pressure in the area.
• Once you have taken care of the sting wound, it’s time to treat your symptoms. An over-the-counter painkiller like ibuprofen should help with the pain. If the stung area is itchy, apply a calamine lotion or a mix of water and baking soda.

Generally, the swelling and the pain subside within two to five days.

Frequently asked questions

Are parasitic wasps poisonous?

Parasitic wasps like ichneumon, braconid, and chalcid wasps may have venom in their stingers, but it isn’t potent against humans. These wasps are poisonous only to other insects.

Does a short-tailed ichneumon wasp sting?

Yes, the short-tailed ichneumon wasp is capable of stinging. However, its sting doesn’t contain any venom, so even when stung, you are completely safe.

Can Pimpla Rufipes sting humans?

A Pimpla Rufipes has cytotoxic venom in its sting, but fortunately, it isn’t dangerous to humans at all. These wasps mostly target butterfly caterpillars or their larvae to lay eggs.

What wasp has a really long stinger?

The giant ichneumon wasp is one of the largest parasitoid wasps, with a stinger/ovipositor that is four to five inches in length. They usually choose horntail larvae as their host.

Wrapping up

Ichneumon wasps come in several varieties. These wood borers vary in appearance but are usually slender. They can either be bright or dark in color. The scorpion wasp, an ichneumon species, has yellow bands on its abdomen.

Regardless of the species, you may rest assured that they’re completely harmless and help protect your garden from pests.

Reader Emails

Over the years, our readers have sent us several emails on this topic. Please go through them below.

Letter 1 – Stinging Ichneumon

Subject: Flying stinger bug
Location: Fort Worth, TX
May 29, 2016 8:15 pm
This flying insects just painfully bit my husband. No itching or welt left behind. We are in North Texas in early Summer.
Signature: B.Mann

Dear B. Mann,
This is a Short Tailed Ichneumon in the genus Ophion, and we believe these are the insects that folks write about when they claim to have been stung by a Crane Fly.  According to BugGuide:  “Most all Ophion larva are parasites of caterpillars.”  Your submission will not post live to our site until mid-June during our annual absence from the office.

Letter 2 – Short-Tailed Ichneumon stings woman in Kansas

Subject: This bug hurt me. What is it?
Location: Central Kansas (Valley Center, Kansas)
April 16, 2017 8:52 pm
I let my dogs in around 9:45 pm and in came two of these bugs. One stung me, I actually screamed because it hurt. An hour later it still hurts. I need to know what this bug is or my 10 yr old will never go outside again. I live near a pond and I am in Valley Center, Kansas this is located in the central part of the state. 4-16-2017
Signature: C.Waller

Dear C. Waller,
This is a Short-Tailed Ichneumon in the subfamily Ophioninae, a parasitoid wasp that we believe is to blame for many reports we receive of stinging Crane Flies.  Short-Tailed Ichneumons are attracted to lights, and that might be the reason they entered your home at 9:45 PM.  Though painful, the sting is not considered dangerous.  You might have to rethink restricting the activities of your ten-year old since BugGuide data has the range of Ophioninae as most of North America, with only four states providing no reports:  Montana, Wyoming and the Dakotas.  That does not mean they do not exist there, merely that there have been no BugGuide sightings.

Letter 3 – Stinging Ichneumon from the UK

Subject:  Identify bug
Geographic location of the bug:  Leicestershire, UK
Date: 07/16/2021
Time: 01:56 PM EDT
Your letter to the bugman:  This was flying around my room at night, I thought it was a daddy long longs and grasped it in two hands. After a couple seconds, it “stung” me as I felt a very sharp prick on my hand.
As I closed it into just one hand to open the window, i felt another very sharp prick – so much so that I quickly released it to move away.
The pain continued in both areas for a fair few minutes and after trapping it in a glass, I managed to take a few pictures before releasing it.
It’s about the size of a daddy long legs, but is red with a “sting” on the end (where it is black) and “spikes” on its legs.  I’ve never seen it before, let alone have one mildly hurt me.
Any information would be greatly appreciated.
How you want your letter signed:  Jack

Dear Jack,
This is a parasitoid Ichneumon Wasp, and there are some species that are capable of stinging as you have learned first-hand.  Of the species pictured on the Natural History Museum Beginner’s Guide to Identifying British Ichneumonids, we believe it looks most like Callajoppa exaltatoria, which is also pictured on Ukranian Biodiversity Information Network.  Though the coloration is similar to your individual, we do not believe they are the same species as other anatomical features appear different.  Ichneumons can be very difficult to identify with certainty.

Letter 4 – Stinging Ichneumon

stinger
Hi there. My wife won’t squash most bugs; she captures the critters and tosses them outside. Yesterday she thought she was saving a crane fly, but when she cupped it in her hand, whatever it was gave her a nice sting. Later in the day I found it and took its picture. Unfortunately, the process seems to have sent it to its final reward. I’m attaching the mugshots. Can you identify it? Thanks.
Russ
Topanga, CA

Hi Russ,
We thought this looked like an Ichneumon, but had never heard of them stinging. So, we wrote to Eric Eaton and he wrote back with this surprising reply: “Yes to both! It IS an ichneumon, probably in the Ophionini tribe, and they are among the few ichneumons capable of stinging. I had been under the impression that NO ichneumons could sting, but that is WRONG. Some apparently paralyze their host caterpillars long enough to drive an egg into them. Goes to show that I’m still learning basic information myself. Eric”

Letter 5 – Stinging Ichneumon

Subject: Wasp or mayfly?
Location: Victorville, California
March 21, 2016 9:53 am
There are a large number of these bugs around our house. They seem to be attracted to our porch lights and congregate in groups of anywhere to 20 to more than 50. Some flew into our house last night and I think I got stung or bit while picking one up to take back outside. They also move like wasps but don’t seem to be very aggressive. However they seem to die very quickly – I swept our porch yesterday and this morning there are dozens of dead or dying ones, which makes me think they are may flies. I tried doing some Google searches but didn’t find a lot of information. Any help is very much appreciated, as we have a small dog and a newborn.
Signature: Melissa

Dear Melissa,
This is an Ichneumon in the Ophionini tribe, and it is a member of a family of parasitic Wasps that are usually very host specific.  We believe this is the creature that is frequently confused with Crane Flies, especially when folks claim to have been stung by a Crane Fly.

Correction:  Netelia species
We just received a comment that while we have the family correct, the tribe and genus are not.  See BugGuide.

Letter 6 – Stinging Ichneumon confused with Crane Fly

Subject:  Images of crane-fly-like-insect (probably Ichneumon?) that stung me
Geographic location of the bug:  Grants Pass, Oregon
Date: 06/03/2019
Time: 07:19 PM EDT
Your letter to the bugman:  Hi there. A couple of weeks ago, when traveling through Ashland OR, I was surprised when something I thought was a harmless crane fly stung me! I was so surprised, having always been taught they are harmless, that I took the internet to look this up, and found your site. I added a comment to this thread: https://www.whatsthatbug.com/2017/04/08/stinging-crane-fly
A week later, in Grants Pass, OR, I saw this one sitting still on a wall and was able to get a picture. I can’t guarantee it’s the same thing that stung me, as I didn’t get to see this one flying, and I didn’t get to see the one that stung me sitting still. But it’s about the same size and look as the one that stung me. And this looks a lot more to me like the Ichneumon referenced in some of your posts about crane fly stings. It’s pretty clearly not a crane fly. I haven’t found anything that describes how the Ichneumon flies – but if it’s similar to a crane fly, then I bet this is what stung me.
How you want your letter signed:  Seneca

Dear Seneca,
As your letter indicates, you cannot be certain this was the insect that stung you, but it is an Ichneumon and it is easy to see why it might be confused with a Crane Fly.  We have also always learned that Crane Flies are harmless and they neither sting nor bite, but we keep getting submissions to the contrary, including a very convincing letter that included both the Crane Fly and the “sting”.

Thank you so much for your reply!
I’m really glad to be learning more about these insects.
Do you know if the Ichneumon flies awkwardly about much like a crane fly?
I never knew there was an insect that could sting that looked and flew so much like a crane fly.
This one had come into our camper van attracted to the light and flitting about and I just assumed it was harmless and cupped it gently in my hands to put it out.
Now I know to be more careful!
I should probably know better than to assume anything anyway. There’s so much I don’t know about so many things.

Hi again Seneca,
Crane Flies have a much more gangly and awkward flight.

Letter 7 – Stinging Ichneumon mistaken for Crane Fly

Subject:  Crane fly sting
Geographic location of the bug:  Eau Claire WI USA
Date: 05/29/2019
Time: 11:59 PM EDT
Your letter to the bugman:  Hello,
I’ve been reading that the crane fly is harmless and does not bite or sting. I was outdoors this evening and felt a sudden sting under my shirt, I instinctively grabbed and squeezed the offender. The sting was intense and spread under the skin like tiny lightning bolts. I have attached a picture of the insect and the bite area.
I also have the specimen in a bag I’m willing to mail at your request.
How you want your letter signed:  Shelly K

Dear Shelly,
We have always relied on the response from experts, including Dr. Chen Young, that Crane Flies neither sting nor bite, and we have had numerous inquiries that dispute that opinion.  We even have a posting with a Crane Fly and what appears to be a sting perpetrated by the pictured Crane Fly.  For years we have also suggested that the perpetrator might be an Ichneumon, a parasitoid Wasp.  In your case, the pictured insect is an Ichneumon, not a Crane Fly.

Letter 8 – Ichneumon Sting, NOT Crane Fly

Subject:  Whats this bug?
Geographic location of the bug:  Elgin,TX
Date: 03/25/2019
Time: 02:10 AM EDT
Your letter to the bugman:  This evening for the first time I got stung by what at least I thought was harmless “Mosquito Hawk”.My skin is still very hot,itchy,and burning 2 hours later.One difference I noticed from posted photo’s is much longer antenae that curl on the ends. (Elgin Texas)
How you want your letter signed:  M.McCartney

Dear M.McCartney,
We get numerous emails and comments from folks claiming to have been stung by a Crane Fly, AKA Mosquito Hawk, and despite our repeated responses that Crane Flies do not bite nor sting, a stand supported by Crane Fly expert Chen Young, folks still claim the Crane Fly to be the culprit.  Your image is of an Ichneumon, a parasitoid wasp.  Most Ichneumons are harmless to people, but one genus, Ophion, is capable of stinging.  Your Ichneumon appears to belong to that genus.

Letter 9 – Ichneumon stings pregnant wife!!!

Subject: Tan flying bug
Location: Central New Jersey, United States
August 26, 2014 6:55 pm
The big just bit my wife. She is pregnant. Should I be concerened? It’s August (obviously) and hot out.
Signature: Mike

Hi Mike,
This looks like a parasitic wasp known as an Ichneumon to us, and we believe she was stung, not bitten.  We don’t believe there is any cause for concern, but we are not medical professionals nor are we entomologists, so if you have any doubts, we would urge a visit to the doctor.

Letter 10 – Wasp stings man in Baja

Subject: Insect information
Location: Baja California
March 30, 2017 9:44 pm
Found this in sanfelipe Baja mexico, after I woke up with a bite on my are that swelled quickly. Wondering if it could be the cause.
Signature: Josh gordon

Dear Josh,
If this is the culprit, you were stung and not bitten.  This looks like a Short-Tailed Ichneumon, possibly in the genus Ophion.  Most Ichneumons are harmless, but members of the genus Ophion are capable of stinging.  According to BugGuide:  “Adult Ophion species will hunt for their host caterpillar. Usually one egg is laid per host. Caterpillar usually dies during pupal stage though wasp larva remains to pupate itself.”

Update:  September 27, 2019
Based on a comment we just received that needs considerable research, we are no longer categorizing this an an Ichneumon.

Letter 11 – Short Tailed Ichneumon Stings human

Subject:  Large gold flying mosquito
Geographic location of the bug:  Crossville, TN
Date: 08/01/2018
Time: 01:01 AM EDT
Your letter to the bugman:  I got bit by this gold flying insect and it felt like a sting? Just trying to identify
How you want your letter signed:  HH

Dear HH,
This is a parasitoid Short-Tailed Ichneumon, probably in the genus Ophion.  We were surprised to learn many years ago that this group is rather unique among Ichneumons in that they are capable of stinging humans.  According to BugGuide:  “Most all Ophion larva are parasites of caterpillars.”

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Giant Ichneumons

bug with long tail
I figured out from your website that this is probably the Giant Ichneumon. I just thought you might like a couple of more pictures. These were taken on a dead stump in a suburb of Minneapolis, MN.
Mike

Hi Mike,
Thank you for sending in your lovely image of Megarhyssa atrata, the most commonly depicted Giant Ichneumon in written texts. IT is your second photo that really impresses us. You have captured that female Megarhyssa atrata ovipositing while a female Megarhyssa macrurus (we believe) looks on. Your photos are great.

Letter 2 – Two Species of Megarhyssa

Giant Ichneumon Coloring
Found these terrifying gentle giants in my backyard today. I was wondering what the difference is between the beautiful yellow-auburn colored ones and the shiny black one. There was only one shiny black one that I could see and it was the only one flying around the tree. All the rest were hanging out, depositing their eggs. Thanks!
Jera

Hi Jera,
Your photo shows two species from the genus Megarhyssa. The black specimen is Megarhyssa atrata, the species typically called the Giant Ichneumon. The brown specimen is probably Megarhyssa macrurus.

Letter 3 – Ichneumon Soap

Anecdote
An humorous, albeit tragic, anecdote that I thought you might enjoy: I work in a paving/construction office which is connected to a large open garage/storage area which is rather exposed to the outside. Our safety director needed some papers that had been stored away in the mezzanine area above the garage. While in the mezzanine, she encountered this Giant Ichneumon, which repeatedly “dive-bombed” her. Not knowing what this bug was and mistaking its ovipositor for a monstrous stinger, she screamed, tripped and fell, wet herself (luckily she had a pair of extra pants downstairs), and continued screaming, drawing a small crowd of concerned coworkers who gathered at the bottom of the stairway to the mezzanine. One brave individual ran upstairs and, sadly, killed the poor bug as our safety director ran down the stairs ranting about its gigantic proportions and “prehistoric” features. Intrigued by her tale of wonder, a coworker and I went up to look at the dead bug, and were intrigued but unimpressed. There were many guesses as to what the bug was, ranging from a mayfly, to a cicada wasp, to a robber fly, but thanks to your website I was able to determine that it was a Giant Ichneumon. My coworker took the dead bug home and placed it into some heated glycerine to form the bar of soap pictured, so that it could preserved and returned to our safety director to commemorate the event. While I know the insect’s untimely death is saddening, I found this story to be too ridiculous to not send to you. Thanks for your amazing website!!!
Jen Price

Hi Jen,
We are greatly amused at the irony that your safety director tripped and fell running from a totally harmless Giant Ichneumon. Surely, thousands of needless accidents occur, perhaps even daily, because of the fear generated by arthropod encounters. We are also amused as we toyed with the idea of having homemade soaps with plastic insects imbedded inside made available on our giftshop page.

Letter 4 – Giant Ichneumon

Long tailed wasp
Hi Bugman,
I tried looking on your site earlier today and couldn’t identify this. My mom spent a bit more time on the site and was able to identify this bug as a type of wasp. What we’re wondering is what it was doing. It kept flipping its body up over its head and holding on to the long tail with its back legs, then pulling. It was doing this for hours. It looked like the wasp was trying to pull the tail off! Do they do this?
The Demeritt Family

Hi Demeritt Family,
We can’t imagine how you missed the photo of the Giant Ichneumon on our homepage. This is Megarhyssa atrata, a female. The long tail is an ovipositor that the female uses to lay eggs deep inside rotting wood of trees. Such wood is often infested by wood boring grubs, especially those of the Pigeon Horntail, and those grubs are the food for the young larval Ichneumon. The odd thing about your photo is that the Ichneumon is trying to lay eggs in wooden siding. Perhaps you have a grub infestation.

Letter 5 – Giant Ichneumon

Whats this bug?
I have been cutting wood at my home in Northern Michigan, about 40 miles South East of Traverse City. I have been noticing these strange wasp like insects boring holes in dead trees. Today we were building a new wood shed and I snapped the second picture of one of these insects on a tree. Can you please tell me what this is? You are more than welcome to post my question and your answer along with these pictures on your web site for others to see. Thanking you in Advance,
Ron & Diane Loveland
First time we saw one of these creatures.Second picture. Notice the strange thing hanging off its tail…. What is it?

Hi Ron and Diane,
Sorry for the delay. We had technical problems and are trying to answer a few backlogged letters. This is a Giant Ichneumon, Megarhyssa atrata, a female. She is laying eggs in wood that is infested with boring insects, like the Pigeon Horntail. The young Ichneumon parasitized the boring insects. The membrane visible in one photo is part of the egg laying process.

Letter 6 – Giant Ichneumon

Great pic but don’t know what it is? Maybe a tree wasp cousin?
Shot this pic 3 days ago in our backyard. A friend said it is kind of a tree wasp that uses its orange feelers to locate bugs under tree bark, then drills into the bark and inserts an egg into the bug via the black feeler. Pretty fancy work! Don’t know its name.
Ian Taylor
Huntsville, Ontario

Hi Ian,
What a truly spectacular photo of a Giant Ichneumon, Megarhyssa atrata. The explanation your friend gave you is essentially correct.

Letter 7 – Giant Ichneumon

Can you tell us what this insect is? I’m 70 and this is the first one I’ve seen.
Thanks,
Geoff Bowles.

Hi Geoff,
This is a Giant Ichneumon in the genus Megarhyssa, probably Megarhyssa macrurus. The female uses that long ovipositor to deposit an egg deep in dead and dying wood because her larva will parasitize wood boring insects found there.

Letter 8 – Giant Ichneumon

Identification Help Please
Could you help me identify this bug? It was photographed in western North Carolina last week. I have lived here 30 years and never seen anything like it.Thanks in advance,
Kevin

Hi Kevin,
What a great photo of Megarhyssa atrata, one of the Giant Ichneumons.

Letter 9 – Giant Ichneumon

what kind of bug is this one?
This looks an awful lot like a wasp but is much bigger. The body is around 2.5" and the "stinger" is about 3-4" long. It has 1 pair of wings , 6 leggs, and two antena. I took the pix on our Maple tree out back, and we live in Northwest Oklahoma. thanks for your help.
Judy Morris

Hi Judy,
This is a harmless Giant Ichneumon, probably Megarhyssa macrurus. Your backlit photo is quite stunning.

Letter 10 – Hoard of Giant Ichneumons

Help
Please tell me what these are and if I should be concerned about small children in the area. They have been hanging out on a wood pile of recently cut trees. As you can see they have a long spikey tail, some have purple wings and some don’t. They sometimes swarm if you get too close. We call them freaky bugs cause they are freaking us out! Please help.
NC
Southeastern Pennsylvania

Hi NC,
This is a Giant Ichneumon in the genus Megarhyssa and it is a beneficial insect, not at all dangerous to you or your children. They are parasitic wasps that do not sting. Eggs are laid deep in the wood where the larval food source, wood boring insects live. Your wood pile must be infested with wood boring insects to attract such a hoard of Ichneumons.

Letter 11 – Megarhyssa in Britain

Is this a Giant Ichneumon?
Hello there.
Great site. I had this bug on my windscreen for two hundred miles un a journy between my house and my parents. Have asked friends but none of them has ever seen one before. looking at your site I presume it is a Giant Ichneumon? Do you know if they are very common in England?
Thanks
Rob Powley

Hi Rob,
We spent some time searching for information and cannot determine if Giant Ichneumons in the genus Megarhyssa are native to England, but we did find some information about them being imported to use as biological controls for wood boring larvae. This is a Megarhyssa, but we are not sure of the species.

Letter 12 – Megarhyssa macrurus

Giant Ichneumon
I figured out what this was by checking your website. I thought you might enjoy these photos from my back yard in a northwestern suburb of Chicago. I have never seen anything like this species before and almost crawled out of my skin when I saw them crawling all over a dead elm in my yard. The tree died after being infested with wood boring bees a couple of years ago.
Thanks for the info!

There are probably still wood boring grubs in your tree which is why the Ichneumons are laying eggs.

Ed. Note: (09/17/2005) We now believe this to be Megarhyssa macrurus which can be located on this site.

Letter 13 – Megarhyssa atrata

Flying Insect
Dear Bugman,
I found this insect on a dead tree stump. It is quite large with the dual black tail at least 3" long. The bug itself flies, somewhat laboriously, and its body is about 2" long. I found more than one and they seem to be trying to attract a mate. They are sticking their tail into a 1/8" hole while puffing out some device on the end of their tails. The head sure looks like some kind of wasp but I see no stingers. Any ideas?
GF

Hi GF,
Awesome photo of a female Megarhyssa atrata, the Giant Ichneumon, laying her eggs. She uses that long ovipositor to deposit eggs deep inside trees that are infested with wood boring insects. The eggs hatch and the larvae eat the grubs that are eating the wood.

Letter 14 – Megarhyssa species

Giant Ichneumon
Dear Bugman:
A friend pointed me to your website, WOW, really great site to visit, I have been trying to find someone who could identify this Insect, behold I think I found it on your website. It is a Female Giant Ichneumon, Right! Here is a couple of Pictures, this was on a Maple tree at my weekend place in northcentral Pa. Let me know if I am correct, Please.
Thank you so much
Tom B
Allentown, Pa

Hi Tom,
Yes, you have a Giant Ichneumon female, Megarhyssa species. Thanks for the image.

Letter 15 – Megarhyssa atrata

Giant Ichneumon?
After reviewing your site (having had searched through many bug books!), I think this is a Giant Ichneumon. Thought you’d like this picture for your website.
Patricia St.Marie
Massachusetts

Hi Patricia,
Thank you for sending in a textbook quality image of a female Megarhyssa atrata depositing an egg. This is the most commonly pictured of the Giant Ichneumon species. Your photo is glorious. We are thinking of redesigning our archive pages so that a classic image of the insect is prominently featured at the top of the page, and I think your image and letter will be at the top of the Ichneumon page for years to come. thank you so much.

Letter 16 – Meharhyssa atrata: Giant Ichneumon

Bug in my garden
Hi there Bugman!
Thank you for providing everyone with such a wonderful website. Please could you tell me what this insect is? It looks similar to "Giant Ichneumon – Megarhyssa atrata" on your website. Thank you for your help.
Andrew – MA

Hi Andrew,
Your Giant Ichneumon is indeed Megarhyssa atrata. We have gotten several other photos of Megarhyssa species recently, but M. atrata is distinctly black with a yellow head and legs. Thank you for adding to our site and also thank you for your kind words.

Letter 17 – Megarhyssa macrurus laying eggs!!

Would you please help me out and let me know what insect this is. I have attached several photos. The photos were taken of one that was approximately the size of a silverdollar not including the tail which appeared to be about 5 inches long. There are many others in all sizes. I am concerned that these will bite or sting.
Thank you for your time.
Heather Hamilton

Hi Heather,
Wow, great photos of a female Megarhyssa species laying eggs. This is one of the Giant Ichneumons. The female uses that long ovipositor to deposit eggs deep inside wood that is being parasitized by boring grubs. We got another photo from Jared in Columbus Ohio two days ago and while we were in Youngstown Ohio this week, we saw one flying aroung the dead wood of Mom’s dogwood tree. They will not sting.

Ed. Note: (09/17/2005) We now believe this to be Megarhyssa macrurus which can be located on this site.

Update:  April 8, 2014
We are frequently asked if Giant Ichneumons can sting, and we always reply that they cannot.  We just found a fascinating article.  According to Icheumon Wasps by Lloyd Eighme on Skagit.wsu:  “It might frighten you, but if you could watch it long enough you would be amazed at what it does. It lands on the bark of a tree and crawls up and down, tapping with its long antennae, obviously searching for something. Eventually it finds the spot it is looking for and begins to drill into the bark with its long needle-like ovipositor. It has detected the larva of a horntail wasp chewing its tunnel in the wood an inch or more below the surface of the bark. The ovipositor is made up of three stiff threads, hardened by minerals, that fit together with a groove in the center. Vibrating those sharppointed threads forces them into the bark and sapwood of the tree to contact the horntail grub in its tunnel. An egg is forced down the ovipositor to parasitize the grub. If the ichneumon parasite larva killed its host, they would both die, trapped in the solid wood which the parasite is unable to chew. It only feeds on the nonvital organs like the fat body until its host has nearly completed its life cycle and has chewed its way out near the surface of the bark. Then it kills and consumes its host grub and completes its own life cycle to emerge as another giant ichneumon wasp in the genus Megarhyssa (mega=large; rhyssa=tail) to start over again. You can see both Megarhyssa and its horntail wasp host in the MG collection.
People often ask if the ichneumon wasps will sting them with their needle-like ovipositors. The wasps are interested only in laying eggs in caterpillars or other insects, but if you handle a live one it may try to sting you in self-defense. Small ones could not likely penetrate your skin, but larger ones might be able to

Letter 18 – Megarhyssa atrata

Big bug, Chicago IL area
Hello,
I hope you can help, this is the biggest bug I’ve seen around here – okay, insect. It’s a flying insect, yellow legs, about 1.2" – 1.5" long (not counting antennae), with a huge "tail", probably 4" long –
actually some kind of boring tool. There were several of these flying insects on a tree, looked like an elm that died within the last year (top branches’ bark were coming off, but not the lower trunk yet, where these bugs were), and they were boring holes into the tree, I assume to lay eggs, although that tail was too thin for eggs it looked like. The tail at first glance was one long tail, but then you could see there were a couple parts to it that were often kept together. I’m including two pictures, one a profile while it was boring into the tree, another after it flew into the leaves, and you can see its tail hanging down and just how long that is. Some of them had different shaped/colored thingies on the end of their abdomen, this one had the clear/silver disc thing. My immediate concern was an Asian long-horned beetle or emerald ash borer, but it was neither of those (also big bugs, with long appendages), so I assume it’s not something too nasty.
Rob

Hi Rob,
What a colorfly descriptive account of the egg laying process of a Giant Ichneumon, in your case Megarhyssa atrata. Her young will feed on the boring insects inside the dead elm tree, insects which might even be responsible for the tree’s demise, so the Ichneumon will help prevent a future tree loss.

Letter 19 – Giant Ichneumon: Megarhyssa species

Unidentified bug
Hi, I live near Columbus, Ohio. I saw the attached wasp looking insect on my back porch. It has a very long tail attached. I’ve never seen anything like it before. Any idea what it is?
Thanks,
Jared

Hi Jared,
You have sent in a photo of a Giant Ichneumon, Megarhyssa species. This is a harmless wasp, in your case a female. She uses that long ovipositor to lay an egg on a wood boring grub. Her young then feeds off the grub.

Letter 20 – Megarhyssa nortoni

Giant Ichneumon
I found this wasp name while searching your web site for pictures to identify a "bug". Now I cannot sleep until I know more about this wasp….if of course I have identified it correctly. You called it a "Giant Ichneumon" in response to an email sent to you by someone else. I think I have one under a glass in my family room….too afraid to move it. I have 3 kids and a dog. This wasp has a black skinny "tail" that is at least 2 inches long and 6 legs that are orange/yellowish and a long skinny body. Did I mention the long antennas? When I look up Ichneumon as a general web search…I don’t get to far with any additional info. What do I do with it and are there many more lurking about? AAaaaghhhh! We live in the pacific northwest. Thanks for any info. I did take pics and will send one on if you need to see it. Thank you in advance,
R. Frances

Dear R. Frances,
Though they are wasps, Giant Ichneumons do not sting. That is an ovipositor for laying eggs deep inside trees where the larvae hunt wood borers. They are beneficial insects for that reason. Try doing a search for the scientific name Megarhyssa atrata for more information.

Photos of Megarhyssa nortoni
Hi Daniel,
Thanks for your quick response….here are 6 lovely photos of the Megarhyssa atrata or Giant Ichneumon. So glad to hear that the tail is not the stinger!! And you will be glad to note my husband released her this morning to the outside. Kinda curious where they are originally found as I have lived in the Seattle area for 30 years and have not seen one here before. Thanks Daniel!
R. Frances

Hi again R. Frances,
After seeing your photos, we can agree they are an Ichneumon of some sort, but the coloring seems a little off for Megarhyssa atrata, though it could be a local variation.
Ed. Note: (09/06/2004) Eric just wrote in identifying this as Megarhyssa nortoni.

Letter 21 – Male Giant Ichneumon

Ichneumon on log
Sir-
Would this be a male Megarhyussa atrata? I was in a woods in Erie Co., OH

Yes sir, this is a male Giant Ichneumon, Megarhyssa atrata, or possibly another species in the genus. We cannot imagine that they are that rare, though most all of the images we receive are of female Giant Ichenumons.

Letter 22 – Megarhyssa macrurus

Photos of Giant Ichnerumons, Megarhyssa Macrurus
I was able to identify Giant Ichnerumons, Megarhyssa Macrurus thanks to your site – we have a dead tree that is covered with them here in Bolton, Connecticut. I am sending you the photos in case they are shots of the bug that you don’t already have. It looks like her ovipositor might be depositing her eggs??? Enjoyed your site. I’ve bookmarked it for future reference. Keep up the great work.
Betty

Hi Betty,
It has been several months since we have posted a photo of a Giant Ichneumon on our homepage. Your photo of a female Megarhyssa macrurus ovipositing is stunning.

Letter 23 – Ichneumon Couple

Male and Female Megarhyssa macrurus
Hi!
We were at our cottage in Holland, MI and were lucky enough to witness 2 female Ichneumon Megarhyssa macrurus depositing their eggs, while a couple of males observed. I noticed that have quite a few pictures of the females on your site – and thought you might like a couple photos of the males! Thanks for your amazing site that helped me to identify this fascinating creature 🙂 We had a great science lesson for all the kids (and adults too) to learn as much as we could after we figured out what we saw! Everyone was relieved to find out they are not stinging insects and were safe to be around 🙂 Sincerely,
Kristen Miles
Grand Rapids, MI

Hi Kristen,
Your amazing photos are a wonderful addition to our site. Now our readers will know what the male Megarhyssa macrurus looks like.

Letter 24 – Giant Ichneumon: Mating Activity

Mystery Bug
I have taken pictures of this bug now for the last two years but it has been coming to a tree in my yard for the last four years and around the same time each year. The pictures I have are from 2006 and 2007 in early to late June. The first three years there was only one of these bugs. In 2007 there was family. I hope you can let me know what kind of insect this is. Thanks,
Bryan Soukup

Hi Bryan,
The group photo you have submitted shows a group of Giant Ichneumons, Megarhyssa atrata, in the process of laying eggs and probably mating. The female has the long stinger-like ovipositor that she uses to lay eggs in the wood. The food for the larvae are wood boring grubs. The males are smaller and do not possess the ovipositor. The single image is of a female. The Giant Ichneumons will not sting you as they are incabable. We wish your group photo had been closer. Perhaps this year you can get us a nice close-up of the males and females together.

Letter 25 – Ichneumon

hey what is this bug??
i found it in my back yard in brier Washington. im going to collage to become an entomologist!!!!! thank you so much, i hope you can tell me what i found!!!!!!!
blake oswold

Hi Blake,
This is an Ichneumon. We are inclined to guess that it is a Megarhyssa species, but it does not match any specimens on BugGuide. In 2004, we received a nearly identical specimen that Eric Eaton identified as Megarhyssa nortoni. The specimens pictured on BugGuide are brown and yellow, not black and white, which has us puzzled. There is also a photo posted on an Australian website where Megarhyssa nortoni has been introduced as a biological control agent for the European Wood Wasp, Sirex noctilio. Eric Eaton quickly wrote back with this comment: “Hi, Daniel: Well, I’m wondering now if the ichneumons are even in the GENUS Megarhyssa! I can’t be absolutely positive. I know there are sizable ichneumons in other genera that closely resemble Megarhyssa, especially in the western U.S. Eric”

Letter 26 – Megarhyssa atrata: Males waiting for the emergence of a female?

WNY Wasps
Fantastic site! These wasps(?) were located at the edge of a hollowed out section of a tree in southwestern New York State. Could they be male and female American Pelecinid Wasps? I’m not positive because their coloration is somewhat different from others I have seen. Thanks.
Kevin

Hi Kevin,
We believe these are male Giant Ichneumons, Megarhyssa atrata. Eric Eaton writes on BugGuide: “I did some reading recently, and apparently that shovel-like appendange on the end of his abdomen allows him to mate with a female while she is still in the tree, prior to her emergence! Sometimes you will see a group of males waiting patiently for a female to emerge from a log or dead standing tree.”

Letter 27 – Megarhyssa macrurus

Ichneumon
Hi,
Last weekend I was lucky enough to observe a large meeting of Ichneumons (dozens at times), males and females, on a bug stressed elm tree in Prescott, AZ. Our local ‘bugman’ Carl Olson, associate Curator of the Dept. of entomology of the U of AZ, was so kind to identify them for me: Megarhyssa (I got that far with my German Insect book and your site) macrurus icerosticta (Michener). The males in the first pic are around 1", the females including the ovipositor up to 5". This all happened during an outdoor art show, so instead of selling my paintings, I found myself explaining over and over again the complex procreation of Ichneumon to lots of curious and fascinated folks.
Margarethe

Hi again Margarethe,
We are especially interested in the photo of the male Ichneumons since we almost always get requests to identify females.

Letter 28 – Ichneumon

Giant ichneumon wasp
I thought you might want a pic of a giant ichneumon wasp. Body length: 3 inches, ovipositor: 3.5 inches, total 6.5 inches! At first I thought it was some type of crane fly, because it did not have the typical wasp shape, but I think it is a megarhyssa ichneumon wasp. It let me get to as close as 12 inches then got nervous if I got closer. The stump is a maple stump. It is trying to lay eggs in an existing hole.
Chuck
Grand Rapids, MI

Hi Chuck,
This is an Ichnuemon, Megarhyssa macrurus.

Letter 29 – Toe-Biter and Giant Ichneumon

2 bugs
The first i assume is a "toe bitter" i have lived in maien my whole life and never seen a bug that big…. heres some photos for you(there were taken on my palm pilot so there not the best)

the second bug i have only seen twice in my life, when i was 6 and noone belived me and jsut a week ago, no photos it however it body is aprox 1 inch from head to tail, look like a hornet, black in color, however it has a 5inch long "stinger" i cant find anythign about it. please help, its like a black hornet with a 5 inch tail. Thanks
Drop me a line when you figure that one out, now that i have foudn yrou website im gonna keep my camera handy for odd lookign bugs 🙂 THANKS for a wonderful service
tim

Hi Tim,
Thanks for the Toe-Biter photo. I know what your second bug is. Here is a photo of a Giant Ichneumon sent in last year. These are wasps, but that five inch long stinger is actually an ovipositor. The female lays her eggs deep inside of a tree trunk and her young are predatory on boring insects, especially sawflies and beetle grubs.

Letter 30 – Male Giant Ichneumon, possibly Megarhyssa atrata, or maybe Megarhyssa macrurus

Looks like a dragonfly, with wasp-like markings
Sun, May 24, 2009 at 6:31 PM
I saw this insect on the side of my house, it was roughly 2 inches long with a similar wingspread. I’m assuming it’s some kind of dragonfly, based on the mouth, wings, and body. I’ve never seen one with markings like this though, it reminds me of a wasp, with striking yellow-on-black. I also don’t recall seeing a dragonfly with antennae ever before. Any idea what this guy is?
Kyle, Hatfield MA
Hatfield, MA

Dear Kyle,
This is a male Giant Ichneumon in the genus Megarhyssa.  Giant Ichneumons are parasitoids that are closely related to wasps, but they do not sting.  Your photo is of particular significance because of its high quality and also because we very infrequently receive images of male Giant Ichneumons.  In July 2007, we received a wonderful image of several males awaiting the emergence of a female.   BugGuide has a photo of a male Megarhyssa atrata, the species we believe you have photographed, and the posting contains a significant commentary posing the possibility that it might be a related species, Megarhyssa macrurus, also a possibility in your case.  Most of the images we receive of Giant Ichneumons are of females, and a large number are ovipositing.  The female has an ovipositor that can be as long as four inches, and many of our readers mistake this for a stinger.  The female uses her ovipositor to deposit eggs deep inside dead and dying wood that contains wood boring grubs, often the larvae of the Pigeon Horntail.

Update:  April 8, 2014
We are frequently asked if Giant Ichneumons can sting, and we always reply that they cannot.  We just found a fascinating article.  According to Icheumon Wasps by Lloyd Eighme on Skagit.wsu:  “It might frighten you, but if you could watch it long enough you would be amazed at what it does. It lands on the bark of a tree and crawls up and down, tapping with its long antennae, obviously searching for something. Eventually it finds the spot it is looking for and begins to drill into the bark with its long needle-like ovipositor. It has detected the larva of a horntail wasp chewing its tunnel in the wood an inch or more below the surface of the bark. The ovipositor is made up of three stiff threads, hardened by minerals, that fit together with a groove in the center. Vibrating those sharppointed threads forces them into the bark and sapwood of the tree to contact the horntail grub in its tunnel. An egg is forced down the ovipositor to parasitize the grub. If the ichneumon parasite larva killed its host, they would both die, trapped in the solid wood which the parasite is unable to chew. It only feeds on the nonvital organs like the fat body until its host has nearly completed its life cycle and has chewed its way out near the surface of the bark. Then it kills and consumes its host grub and completes its own life cycle to emerge as another giant ichneumon wasp in the genus Megarhyssa (mega=large; rhyssa=tail) to start over again. You can see both Megarhyssa and its horntail wasp host in the MG collection.
People often ask if the ichneumon wasps will sting them with their needle-like ovipositors. The wasps are interested only in laying eggs in caterpillars or other insects, but if you handle a live one it may try to sting you in self-defense. Small ones could not likely penetrate your skin, but larger ones might be able to

Letter 31 – Giant Ichneumon: Dead from involuntary insect slaughter

Update:  July 15, 2018
It is never too late to add an overlooked posting to the Nasty Reader Award tag.

Strange wasp
July 25, 2009
This painful creature was found at my ex-husbands house. It came down from the attic (comforting I know). It has, what looks like, three long stingers about three + inches long. It has yello on its head/antennas and very long back legs and black wings.
Samantha
East Tennessee

Dear Samantha,
We are guessing this Giant Ichneumon, Megarhyssa atrata, came down from the attic alive and we are also guessing it is not asleep in this photograph.  We are going to make the leap that is was killed before the photograph was taken.  Giant Ichneumons, despite their frightening appearance, are perfectly harmless.  They are parasitic relatives of wasps and they are incapable of stinging.  What looks like a stinger is in reality the ovipositor of the female and she uses it to lay eggs in the tunnels of wood boring insects like the Pigeon Horntail and other Wood Wasps.  The newly hatched Giant Ichneumon larva then locates the larva of the Wood Wasp and begins to feed upon it.  Coincidentally, we also just received an image of a dead Wood Wasp which we will post next. Since this Giant Ichneumon was killed unnecessarily, we will tag it as Unnecessary Carnage.

I do not appreciate your accusations. It was alive, I had to put it in a container at my ex-husbands house and bring it to mine. It did die on the way over, it was not killed. If I wanted to kill it it would be smooshed, I cannot spray pesticide as my infant is usually close by me. You have been very rude, I will know not to come to you again if I have another question about a bug.
Thanks for your time.

Dear Samantha,
It was not our intention to be rude, but to answer your question as to the identity of your insect, and to try to educate you and others out there about its harmlessness.  The fact that the death of the Giant Ichneumon was involuntary in no way changes that its death was unnecessary, though we are pleased to know that its demise was unintentional.  Insects may die if they are kept for long periods of time in tightly closed containers, and it is surprising how many times unintentional death by suffocation or heat exhaustion occurs, and we are not speaking about insects.  If it is your choice to no longer use this free service that we offer, and we promise we will not force you to visit our site for either educational or entertainment purposes, nor will we demand that you send us additional questions about insects and other arthropods.  In the future, should you have questions about creatures that might potentially harm your infant, you are free to pass over our website and search for your answers elsewhere on the world wide web, and we promise not to blame you for never writing us again.

Letter 32 – Ichneumon: Therion morio

Crane Fly? Damsel Fly? Really Off-Course Fly?
July 31, 2009
Hey there – Here’s a very interesting looking flying insect found yesterday, July 30th, at Massassauga Point Conservation Area, Prince Edward County, Ontario. Very sunny day, humid, temperatures around 28 Celsius. My wife works for the conservation authority and was in the field when she spotted it. I’ve done as much Internet searching as I can but cannot identify the insect. It was in a brushy, wooded area when the photo was taken, and when in flight its legs dangled much like a mud dobber, and it has orange antennae like a wood wasp, but it’s the tail end that has us stumped. It hovered much like a wasp when in flight.
Any help would be appreciated – thanks!
Glenn May-Anderson, Belleville, Ontario
Massassauga Point, Prince Edward County, Ontario

Hi Glenn,
We receive many identification requests for female Giant Ichneumons in the genus Megarhyssa, but we receive very few images of the males.  This is a male Megarhyssa atrata.  The female has a three inch long ovipositor that is often mistaken for a stinger.  She uses her ovipositor to deposit eggs into dead and dying wood that is infested with wood boring larvae, the food for the larval Ichneumon.

Correction from Eric Eaton
August 4, 2009
Hi, Daniel:
… A couple other things:
The “Giant ichneumon:  male of the species” is incorrect.  The ichneumon in the image is not even in the same subfamily, and it is likely a female.
… Keep up the great job, Daniel:-)
Eric

Update:  Therion morio identified
August 19, 2013
We just received a new photo which we thought might be a male Megarhyssa atrata, but our search for a matching photo led us to this old unidentified Ichneumon.  Searching BugGuide, we discovered it is Therion morio.

Letter 33 – Giant Ichneumon: female of the species

Wood hornet?
July 31, 2009
This bug was flying around the lights in front of my house in Richmond, Virginia on the night of July 29, 2009. I think it could be a wood hornet and I think the whip-like tail could be an ovipositor (thanks to the information your website provided!) but I am not sure. If this is an ovipositor, why is it so long? It seemed as though the bug had very little control of it as it flew around the lights and banged into the side of the house!
Steph
Richmond, VA

Hi Steph,
Coincidentally, a few minutes ago we posted an image of a male Megarhyssa atrata, and in that response, we described the female.  Your photo is a female Giant Ichneumon, Megarhyssa atrata.  She does have an ovipositor.  Giant Ichneumons prey upon the larvae of Pigeon Horntails and other wood boring insects that infest dead and dying trees.  The female uses her long ovipositor to deposit eggs deep inside infested wood, “drilling” until she locates the tunnel of a wood boring grub.  That is where she lays the egg. We have several nice images of Giant Ichnuemons ovipositing on our website, including this one from June 2008.  We have heard that Giant Ichneumons may be attracted to artificial lights at night.

Letter 34 – Giant Ichneumon on Windshield

XL Gold Colored Flying Six-legged Black Tail Bug
September 20, 2009
I was startled, thrown back, shocked and subsequently frozen in my driver’s seat after I saw an insect on my windshield today that I have never seen before. It took me a second to gather myself and try to surmise whether the bug was inside the car or out. Once I gathered that I was safe as the bug was stuck to the outside of the windshield, I pulled over the side of the road to contend with the unknown beast at hand. I took a couple of pictures. The bug was about 5 inches long, excluding the long black antenna looking tail. It was gold/light brown colored, and it had wings. I believe that it had six legs.
Freaked Out
Homewood, IL (Northwest Illinois)

Dear Freaked Out,
We love your chilling first hand account of your encounter with a Giant Ichneumon in the genus Megarhyssa.  We want to allay your fears and assure you that the Giant Ichneumon will not harm you.  What appears to be a stinger is the female’s ovipositor.  She deposits eggs under the  bark of trees infested with wood boring larvae.  The larval Giant Ichneumon parasitizes the wood boring larvae.

Hello, Daniel
Thank you for taking the time to reply, and to reply so promptly, to my identification request.  This is very interesting information that you shared.  Upon your identification, I went online and did more research.  I came across an excerpt that said Charles Darwin was amazed by these creatures as well.  That long black ovipositor is frightening in appearance.
All the best to you,
Colleen

Letter 35 – Giant Ichneumon

unk wasp
Location:  McHenry County,IL.
August 26, 2010 10:22 pm
I saw this wasp next to a path in a forest preserve
sarge

Hello sarge,
Though your email indicates you do not know what this creature is, your name on the digital file indicates you identified it as an Ichneumon, a large family of parasitoid wasps.  We believe, because of the noticeable spots on the wings, the coloration of the body, and the location of the sighting, that your individual is Megarhyssa greenei, one of the Giant Ichneumons.  You can compare your image to photographs posted to BugGuide.

Letter 36 – Giant Ichneumon

Giant Ichneumon land on sternum
Location:  Fairfield, Maine USA
August 27, 2010 11:09 pm
My wife ad I were heading up to our front door when this thing swooped down onto me. It landed on my chest and after a few awkward pictures, it walked up my neck and flew of my ear. It was very long, I would have guessed 5-6 inches, including the ovipositor. Do you think this a Megarhyssa greenei?
Thanks,
James R

Hi James,
We have never read a good way to distinguish the members of the genus Megarhyssa from one another, other than that Megarhyssa atrata looks significantly different from the other three relatives.  This might be Megarhyssa greenei, though in our opinion, it seems to most closely resemble Megarhyssa macrurus, which you may view on BugGuide.

Letter 37 – Giant Ichneumon: Plagiarism on What's That Bug????????????????????????

wasp or horney
Location:  waco, texas
September 14, 2010 9:09 pm
found this in texas
Signature:  Leona Garrett
giggles76692@yahoo.com

Dear Leona Garrett of Waco Texas,
We do not tolerate plagiarism or cheating from our students, and we are shocked that we may have discovered it in a letter submitted to our website.  With all the publicity currently in the press regarding the claims of a lost negative trove attributed to Ansel Adams and the possibility that the glass plates were actually taken by Uncle Earl, we are most sensitive to claims of authenticity.  Kindly explain:   How is it that this exact image that you sent to us and claim to have taken in Waco, Texas in 2010 was identified as Megarhyssa nortoni on BugGuide after being posted by Sandy Mallet with a 2007 copyright in Warwick Massachusetts?  We eagerly await your response.

Letter 38 – Mating Giant Ichneumons

Giant Ichneumon wasp and mates
December 29, 2010 1:32 pm
I wish I would have discovered your web site earlier in the year.  I had the unusual pleasure of discovering the Giant Ichneumon along with her small males in my garage.  It was an awesome experience to see her and two of the smaller blue black males.  They were flying around the garage and attracted to the fluorescent light. At the time I did not know what they were.  My husbands first reaction was to grab the bug spray….needless to say I did not allow that to happen!  Why is it that so many people want to destroy what they do not understand? Anyway, I love your site!
Signature: Kristi Bird

Dear Kristi,
Thanks for sending in an awesome letter.  WE wish you had enclosed a photograph.  We found a photo in our archives that illustrates male Giant Ichneumons congregating around females to accompany your letter in our posting.  It was originally submitted in 2007.

Letter 39 – Giant Ichneumon deposits eggs

What is this in Michigan? A wasp?
Location: Detroit Metro, Michigan
June 3, 2011 8:30 pm
Ew we found this tonight … it looks like it is injecting our tree!!!
Is it a wasp?!
Signature: Noel

Hi Noel,
We want to begin by complimenting you on having taken a beautiful photograph of a female Giant Ichneumon (see BugGuide) in the genus Megarhyssa, most likely Megarhyssa macrurus, in the act of ovipositing or depositing her eggs.  While this probably appears to be detrimental to the tree, the larvae of the Giant Ichneumon does not feed on wood.  Rather, they feed upon the larvae of the wood boring Pigeon Horntail.  The Pigeon Horntail does not generally infest healthy trees, so this tree is most likely already in a state of decline.  Both the Pigeon Horntail and the Giant Ichnuemon belong to the same insect order as bees and wasps, Hymenoptera, but neither the Pigeon Horntail nor the Giant Ichneumon is capable of stinging.  They are wasp-like without being true wasps.  This is our second sighting of a Giant Ichneumon reported today.

Update:
June 5, 2011
We just received and posted a new photo of the host insect, the Pigeon Horntail.

Letter 40 – Giant Ichneumon

Its huge!
Location: Southern New York State (Corning)
June 3, 2011 2:42 pm
We discovered this little guy when we were outside today, the tail on it was about three inches long to give you an idea of the size. I personally have never seen anything with a tail on it, much less the size this thing is.
Signature: Thanks!

This is a female Giant Ichneumon, the second image we received the same day.  The photo we just finished posting shows the female in the act of using that lengthy ovipositor to place her eggs deep within the wood of a tree infested with wood boring larvae.

Letter 41 – Giant Ichneumon

Unknown Bug
Location: Twin Peaks, CA
July 9, 2011 1:13 pm
My Cousin Took A Snapshot Of This Wierd Looking Creature And We Just Want To Know What It Is
Signature: Any

Dear Any,
This is a Giant Ichneumon in the genus Megarhyssa.  Based on the coloration and location, we believe it is Megarhyssa nortoni, and you may compare to this image on BugGuide.  Giant Ichneumons are non-stinging parasitic relatives of bees and wasps, and this female is in the act of laying eggs, known as ovipositing.  She senses that there are wood boring larvae of Wood Wasps in the tree, and they will serve as the host for her own developing larva.

Letter 42 – Giant Ichneumon

Strange Bug?
Location: Zumbro Falls, MN (Mississippi River Vally)
August 14, 2011 3:59 pm
Hi,
We where camping and found this bug on a almost completely dead tree. What we though was a large wasp but after a closer look it wasn’t a wasp but some wasp/mayfly looking thing, we stood there and ask a lot of people walking by, and everyone was stumped, can you help?
Thanks,
Lars
Signature: ?no idea?

Hi Lars,
This Giant Ichnuemon, Megarhyssa atrata, is in the process of laying eggs.  She is a parasitoid member of the wasp and bee order, and her prey are the wood boring larvae of a wood wasp known as the Pigeon Horntail.

Letter 43 – Giant Ichneumon

Weird Insect!!
Location: Batavia, OHIO
October 14, 2011 10:29 pm
I was a few minutes from home today and saw this bug swarming toward my windshield, and finally landed and was whipping some kind of a tail or stinger around. It stayed on the window the rest of the way home and it actually terrified me to get out because I didn’t know if it could sting. What is this bug??
Signature: Mandy H.

Dear Mandy,
We can well imagine your fears considering the appearance of the Giant Ichneumon, however, they are perfectly harmless.  What appears to be a stinger is an ovipositor for laying eggs deep inside tree branches and trunks that are infested with the larvae of wood boring insects.  Stingers of bees and wasps are modified ovipositors, however the ovipositor of the Giant Ichneumon has not been modified to sting.

Letter 44 – Giant Ichneumon

Subject: bees, scorpions, and dragonflys breeding?
Location: Island in New Hampshire
August 6, 2012 6:34 am
Found this insect on an island in New Hampshire beginning of August. Was sitting in a knot in a tree very docile. A similar looking mate was flying around outside. This one barely moved as I got close to take pictures. Looks like it had a stinger like a scorpion, head and upperbody if a bee, and body and wings of a dragon fly. Also had large black like whiskers pertruding off the sides. Very strange insect indeed would love any direction you could point me in with this. -Eric P.
Signature: Eric P.

Hi Eric,
This is a Giant Ichneumon in the genus Megarhyssa, probably Megarhyssa macrurus.  Giant Ichneumons are commonly called Stump Stabbers. The female stabs a stump using her long ovipositor to lay eggs beneath the surface of dead and dying trees that are infested with the wood boring larvae of Wood Wasps.  See BugGuide for additional information.

Wow…such a quick reply, thanks so much! I guess my family and I have picked out names for our discovery in vain. So much for a rare island insect being undiscovered yet!
Thanks again!

Letter 45 – Giant Ichneumon

Subject: unknown flying insect
Location: wilmington ,ma
June 21, 2013 1:55 pm
took this pic on june 20,2013 in wilmington ma.
I took this pic with my camera.
Signature: BrowMaster

Dear BrowMaster,
This is a very unusual angle on a Giant Ichneumon, Megarhyssa atrata, a species that parasitizes wood boring larvae of the Pigeon Horntail.

Letter 46 – Giant Ichneumon from Utah, but which species???

Subject: Have simply no idea, never seen anything like this.
Location: Hinckley Scout Ranch in the High Uintahs
July 19, 2013 7:37 pm
Dearest Bugman,
My 13 year old just got home from Scout Camp held at Hinckley Scout Ranch in the high Uintahs near the border of WY and UT but in Utah. He only took a few photos and one video the entire week, but they were nearly all of this one strange, alien-looking insect, the likes of which I’ve never seen. It looks like something Hollywood would come up with for a sci-fi movie. I’m happy to share the video if you want, but for now I’ll just send photos. As long as we’re talking sci-fi movies, I guess I should end with ”Help me Bugman, You’re my only hope!” 😉
Additional details: From tentacles on the head to tentacle-things out the tail, it was probably no more than 5 inches. There were some thin tentacle things coming out from the tail that could extend more than twice the length as the body, that would flutter when in the air…stingers? Is this some kind of crazy wasp? These tentacles could point straight up, or curl all the way to the ground. It didn’t fly while the scouts were watching it, but seemed to have two small wings.
Signature: Blue

Dear Blue,
We are happy to come to your rescue, and we are thrilled to post your photos.  We are going to begin in a very general manner and hopefully end with what we believe might be a species identification.  This is a Giant Ichneumon in the subfamily Rhyssinae, and we have many photographs members in this subfamily in our archives, but almost all are from the genus Megarhyssa.  We do not believe your individual belongs to that genus.  Your suspicions that this is “some kind of crazy wasp” are correct.  Ichneumons are parasitic Hymenopterans, the order that includes bees and wasps, but they are not classified as wasps.  The five inch long “tentacle” is actually the ovipositor of the female and she uses it to penetrate the wood to lay an egg on the wood boring larvae of Wood Wasps.  According to BugGuide, Rhyssinids are:  “idiobiont ectoparasitoids of the immature wood-boring endopterygote insects, in our area usually larval woodwasps (Siricidae and Xiphydriidae), but may also develop as facultative hyperparasitoids using other woodwasp parasitoids as hosts or on virtually any endopterygote (some have even been cultured in the laboratory on entirely unnatural surrogate hosts).”  Alas, we don’t think many of those words are in our unabridged dictionary.  Your individual most closely resembles Rhyssela nitida which is pictured on BugGuide, however, BugGuide only reports them along the eastern seaboard.  That does not mean they do not range further west, only that BugGuide has not gotten any images from farther west.  Your individual seems to have black wings while the Rhyssela nitida images on BugGuide look like the wings are transparent, so we believe it is a different species.  We will try to get a confirmation on the species, however, we are positively thrilled to have this unrepresented Giant Ichneumon for our archives.

Daniel,
Wow.  I used to think I could read at a high level…just knocked that notion off the the ole’ pedestal! 😉
We are so happy to get your reply.  In case it might help, I have uploaded the video my son took (sorry some parts are shaky…no tripod and a bunch of scouts jostling for position, but there are some good moments) to YouTube so you can take a look.  While I was converting it for YouTube, I paused the video on some of the less-blurry frames and took screen shots. They’re poor quality, but in case some of the images may be of help to you and your colleagues, I’m attaching them to this message. I do apologize for the blurriness…remember they’re just still frame shots from a pretty low-quality camera.
We’re happy to have been able to give you something new to add to the body of knowledge, and look forward to any additional information you come up with.  He mentioned to me that this was in their troop’s actual campsite…a tidbit I didn’t know when I first wrote to you.
Best,
Blue (and Brandon, the kid we owe this to.)

Hi again Blue and Brandon,
As you indicate, the screenshots of the video are blurry, however, they do show the position of the ovipositor as it enters the log, which is quite different from the posture of the members of the genus Megarhyssa when they oviposit.

Hi Daniel,
Well, it’s been several months. We were talking about this the other night and wondering if anything else was ever discovered/decided about the Giant Ichneumon. Were you to have any information we’d love to know more.
Happy Thanksgiving!
Blue

Hi Blue,
We didn’t learn anything new, but often we get comments on posts that are several years old.  We would recommend that you either check the posting with some degree of regularity, or post a comment so you will be notified of any new activity on the posting.

Update November 27, 2013:  Eric Eaton provides a possible identification
I just posted the link to the “Hymenopterist’s Forum” on Facebook.  I’ll let you know if anyone has anything to add.
Daniel:
Only reply so far is from Devon Henderson, a … very knowledgeable authority in Canada.  She thinks it is an ichneumon in the genus Dolichomitus, subfamily Pimplinae.  Judging from posts on Bugguide, that would seem to be a good bet.  Might not be possible to ID it from images alone, though.
Eric

Letter 47 – Giant Ichneumon takes Nectar

Subject: What is this insect?
Location: NE Ohio
September 29, 2013 9:36 am
This was found in Ohio. I’ve never seen an insect like this let along one that has a stinger that long. Approximate size of stinger was 3-4”
Signature: Mike

Hi Mike,
This is a female Giant Ichneumon in the genus Megarhyssa, most likely Megarhyssa macrurus or Megarhyssa nortoni.  Giant Ichneumons are commonly called Stump Stabbers.  What you have mistaken for a stinger is the ovipositor of the female.  A female Stump Stabber inserts her ovipositor beneath the bark of a dead or dying tree that is infested with wood boring larvae of Wood Wasps like the Pigeon Horntail.  Your photo is most interesting for us because we almost always receive images of Stump Stabbers stabbing stumps.  We have read that adults take nectar, and your photo appears to illustrate a nectaring female.

Letter 48 – Giant Ichneumon

Subject: Scared husband, Braconid or ichneumon?
Location: Shelton, CT
October 13, 2013 10:13 pm
My husband found this on his arm today after helping me with some gardening. I’m not sure how it escaped with its life, he’s a bit jittery with the insect world. He came to get me, I assured him the spike as he called it was not to sting him! We are curious what she is and where she would be depositing her eggs. She had some really pretty colors, orange and yellow. Not very graceful in flight though. I put her in my juniper bush to save her from the dog!
Signature: Karen wife if scared husband

Hi Karen,
This is a Giant Ichneumon in the genus Megarhyssa, most likely Megarhyssa macrurus or Megarhyssa nortoni, which are both pictured on BugGuide.

Letter 49 – Flightless Ichneumon from Canada: Gelis species

Subject: What Is It?
Location: Goderich, Ontario, Canada
November 18, 2013 8:52 am
I found this little one on the side of the house. It was about 1 cm long.
Signature: Dale

Dear Dale,
We were immediately excited upon viewing your photo.  We knew that though this looked like an ant, it is more likely a parasitic wasp and judging by the ovipositor, that the individual is female.  We quickly discovered the genus Gelis on BugGuide where we found this matching photo.  According to BugGuide:  “Many species of Gelis are wingless. Habits are diverse. Many are external parasites of Lepidoptera in cocoons, others are parasitic on Symphyta, spiders, Diptera larvae and pupae, or wood-boring Coleoptera larvae. Many are Hyperparasites.”   This is news to us as we did not realize there were wingless Ichneumons.

Letter 50 – Flightless Ichneumon

Subject: what kind of bug is this
Location: columbus ohio
December 26, 2013 5:47 pm
Hi,
Found this bug in my house, 12/26 in ohio…its freezing outside haven’t seen any sig of bug life so to find one inside puzzled me! What type of bug is this? Should I be concerned that there are more? It looks fire antish- I grew up in the south that was my first guess, never seen/noticed anything like it before in OH.
Thanks for any feedback!
Signature: M

Dear M,
We believe this is a flightless Ichneumon in the genus Gelis.  Ichneumons are parasitic wasps that prey on a variety of insects and arthropods, though many Ichneumons are host specific.

Letter 51 – Giant Ichneumon

Subject: Strange wasp? Cape Cod
Location: Cape Cod, MA
July 21, 2014 5:56 am
My niece was in Cape Cod last year and couldn’t identify what this (wasp?) is. I’ve never seen anything like it. She asked several scientists that were there too and they couldn’t either. I don’t know if any were entomologists. It was just hanging out on a picnic table I believe.
Signature: Joe

Hi Joe,
We sincerely doubt that any of the scientists were entomologists, because even those that specialize in other insect orders should recognize a Giant Ichneumon or Stump Stabber in the genus Megarhyssa.  Despite the formidable looking ovipositor, Giant Ichneumons are not aggressive and they are not capable of stinging humans.  With that stated, the ovipositor is used by the female to lay eggs beneath the surface of dead and dying trees and stumps that contain the wood boring larvae of Horntails and Woodwasps, so it might be possible for the ovipositor to pierce human skin, though we think it is highly unlikely for a Stump Stabber to mistake a human limb for an infested tree.  Several members of the genus look very similar, so we are reluctant to attempt a species identification.  Another distinctive member of the genus, Megarhyssa atrata, is our featured Bug of the Month for July 2014.

Letter 52 – Giant Ichnuemon

Subject: Scary looking tail end…
Location: Northern IL
July 25, 2015 3:42 pm
Dear Bugman,
I just finished reading your book and never would have imagined that I would enjoy a book about bugs so much! Then lo and behold, I have an opportunity to submit a bug question. We are in northern Illinois and this scary looking critter just appeared on our window screen. Can you please tell me what it is?
Signature: JP

Dear JP,
How nice to hear you enjoyed Daniel’s book.  This fascinating creature is a Giant Ichneumon, sometimes called a Stump Stabber, in the genus Megarhyssa.  We believe your individual, because of both the patterns in the wings and the striped abdomen, is Megarhyssa macrurus, and you may compare to this image on BugGuide.  The Giant Ichneumons prey upon Horntails or Wood Wasps, including the Pigeon Horntail.  The long ovipositor of the Stump Stabber is required to correctly deposit eggs into branches infested with larval Wood Wasps.

Letter 53 – Giant Ichneumon

Subject: Help with a big bug
Location: Yardley PA
December 5, 2015 2:56 pm
We just spotted this large bug on our window screen. Is it a type of ichneumon wasp?
We live in Yardley PA.
Thanks,
Jessica
Signature: The graffius family

Dear Jessica,
This seems very late in the season for a Giant Ichneumon sighting in Pennsylvania, but this is nonetheless a Giant Ichneumon in the genus Megarhyssa, most likely Megarhyssa macrurus.

Thank you so much for the quick response. It has been unusually warm so maybe that explains it. Can’t wait to tell the kids more about this bug. We get a lot of types at our house.
Jessica

Letter 54 – Giant Ichneumon drinking water

Subject: Cool looking
Location: Michigan
August 11, 2016 4:29 pm
What is this thing in n michigan
Signature: John Peters

Dear John,
This is a Giant Ichneumon in the genus Megarhyssa, most likely Megarhyssa macrurus.  It appears to be drinking from a water fountain.  Please confirm that.  Giant Ichneumons are sometimes called Stump Stabbers because the female uses her long ovipositor to lay eggs that will hatch into larvae that feed on the wood boring larvae of Horntails like the Pigeon Horntail.

Letter 55 – Giant Ichneumon

Subject:  What is this??
Geographic location of the bug:  Southwest iowa
Date: 06/19/2019
Time: 07:37 PM EDT
Your letter to the bugman:  What is this?  Looks like a wasp but for its tail like thing and design on body.  Tail thing comes out of body about 1/4″ from end of body! Coin in the picture is a quarter for visual comparison.
How you want your letter signed:  Concerned Mimi

Dear Concerned Mimi,
This is a harmless, beneficial Giant Ichneumon in the genus Megarhyssa, sometimes called a Stump Stabber because the female uses her lengthy ovipositor to lay her eggs in diseased and dying trees where the larvae will be able to feed on the the wood boring larvae of Horntails.  We believe your individual is Megarhyssa macrurus.

Letter 56 – Giant Ichneumon

Subject:  Strange insect
Geographic location of the bug:  Grain Valley MO
Date: 10/02/2021
Time: 02:56 PM EDT
Your letter to the bugman:  We were coming home from independence we live in in grain valley this was on our windshield
How you want your letter signed:  Lisa Gerlt

Dear Lisa,
This is a Giant Ichneumon in the genus Megarhyssa, probably Megarhyssa macrurus.  Because of the long ovipositor which the female uses to lay eggs beneath the bark of deciduous trees infested with wood boring larvae, they are sometimes called Stump Stabbers.  You can read more about this parasitoid wasp on BugGuide.