The Essential Guide to Understanding Sawflies

folder_openHymenoptera, Insecta
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Despite belonging to the same order as bees, sawflies are far from beneficial. Instead, sawflies are pests that can potentially cause a lot of damage depending on the species. 

There are 7,000 species of sawflies, with a variety of hosts. This article seeks to shed light on these pests and explore effective treatment methods.

sawfly
Elm Sawfly

What Are Sawflies?

They are a group of insects characterized by a saw-like ovipositor, which explains the name. The 7,000 different species are spread across seven different families, which makes the sawflies a very diverse bunch. 

However, all these families belong to the vast superfamily Tenthredinoidea

Sawflies are often easy to mistake for bees, wasps, and hornets and belong to the same order as the – order Hymenoptera. 

They are also referred to as “primitive wasps.” Both adult and larval sawflies are pests, though the extent of damage varies from one species to another.

Types of sawflies

1.     Elm Sawfly

The elm sawfly stands out, especially because its larva is one of the largest sawfly caterpillars in North America. 

If you find a metallic blue fly-like bug with a striped abdomen, it might be an elm sawfly. 

These insects are notorious for defoliating elm and willow trees, though they sometimes infest boxelder, apple, birch, maple, and other tree species. 

Female elm sawflies use their saw-like ovipositors to cut open the leaves of host plants and lay eggs.

2.     Rose sawfly

If you find sawfly larvae on roses, it’s likely the larvae of rose sawflies. Also known as the rose slug sawfly, the adult looks like a black fly with a yellow abdomen. 

It’s mostly their larvae that cause damage, feeding on the soft tissues of rose shrub leaves and exposing the hard tissues inside. 

This skeletonization process badly affects the aesthetic value of the rose shrubs by causing the leaves to turn brown and dry.

sawfly
Elm Sawfly

3.     Pine sawfly

There are several species of pine sawflies out there, among which the European pine sawfly is the most abundant species in North America. 

Adult pine sawflies have black heads and bodies and are dotted with yellow and white spots. 

Some species of pine sawflies give birth to several generations per year, and their larvae are particularly devastating. 

Although they mostly defoliate the crown and the upper part of trees, a pine sawfly infestation can sometimes result in complete defoliation too. 

Defoliation caused after the formation of the winter buds can result in the death of branches or even the whole tree.

4.     Dogwood sawfly

A black fly with a yellow abdomen, dogwood sawflies closely resemble wasps. As their name suggests, dogwood plants are their most preferred host species. 

The adults usually emerge around May to July. Female dogwood flies use their ovipositor to insert up to 100 eggs in a leaf, usually lining them across entire leaves along the veins. 

Leaves with dogwood sawfly eggs are easy to identify, as each egg causes a tiny brown bump to appear. 

Their larvae can be a huge problem because matured caterpillars of this species tend to bore into softwood, including various lawn furniture. 

Interestingly, the larvae of dogwood sawfly take up several appearances, colors, and textures during the molting stages.

sawfly
Dogwood Sawflies

5.     Birch sawfly

Growing up to almost an inch in length, these large sawflies lay their eggs under the bark of birch trees. 

Once again, the saw-shaped ovipositor turns out to be handy. As with all the other pests of this species, the larvae feed on their host plants. 

Thankfully, birch sawflies or their larvae don’t cause a lot of damage or defoliation on birch trees. 

The effects are usually only short-lasting, though young birch plants are more vulnerable to damage.

6.     Raspberry sawfly

The raspberry sawfly is an agricultural pest notorious for feeding on raspberry, loganberry, gooseberry, and blackberry. 

Raspberry plants are their most common hosts but can usually survive sawfly infestations without much issue. 

In most cases, raspberry sawflies only cause small holes in the leaves. Heavy infestations, however, can result in the leaves getting completely skeletonized. 

Adult raspberry sawflies look like stout black wasps, while the larvae are a light green shade,  very similar to the leaves they infest.

Elm Sawfly

Where Do They Live?

Sawflies are very common in the US, and you can find them in every state. 

Besides other North American countries like Canada and Mexico, these pests are also abundant in Japan and Europe. 

Sawflies mostly reside in the temperate zones in the Northern hemisphere. 

While one can still find some species of sawflies in African forests, they’re scarce in Australia and absent in New Zealand. 

As for their preferred habitat, most of them have specific host plant species. As you may have noticed already, the sawfly species are usually named after the plants they prefer to feed on.

What Do They Eat?

Adult sawflies usually feed on pollen and nectar from flowers, but leaves are often a part of their diet too. Besides, they’re also insect predators and may prey on ants. 

It’s the larvae of sawflies that cause the most damage due to their feeding habit. These caterpillars feed on plant tissue, which is why they cause extensive damage to leaves. 

Besides, they also have strong mouthparts that allow them to pierce the bark tunnels and suck out tree sap. 

Although most sawflies have specific host plants, some are relatively more generalist and cause a lot of damage to garden plants.

sawfly
Bottlebrush Sawfly

What is the Lifecycle of sawflies?

Most species of sawflies have a very short lifespan and die within about six months of hatching. They spend most of this time as larvae and get to spend only a week or two as adults. 

However, many sawfly species in Minnesota live up to a year. They have four distinct life stages, like most members of the insect world.

Egg

Their eggs are inserted into plant leaves and petioles and show up as yellow and brown spots on the surface. 

As they develop, they grow in size and often protrude through the surface. 

Depending on the weather and the species, the time taken for them to hatch ranges from two to eight weeks.

Larvae

The larvae of sawflies are commonly grouped as caterpillars due to the similarities in their appearance and behavior. 

Sawfly larvae usually have black spots all over them and move around in groups. When disturbed, all of them tend to rear back their heads together. 

This is a key identifying characteristic that can help you distinguish sawfly larvae from other caterpillars. 

The larval stage lasts two to four months and comprises six instars. 

You might not notice them until they’ve reached the final instar. This is when they start eating large chunks of leaf tissue.

sawfly
Sawfly Larva

Pupae

While some species of sawfly larvae pupate in the soil, others spin cocoons attached to host plant leaves. 

Sawflies take longer to pupate than most common insect species, and this stage may last a few months.

Adults

Finally, the adults emerge and live for up to a couple of weeks. Some sawfly species have longer lifespans and can live for more than a year.

Where Do They Lay Eggs?

Adult female sawflies usually use their ovipositors to insert eggs in plant leaves and petioles. 

The eggs may be laid singly, along leaf veins, or in clusters of 30 to 90 eggs, known as pods or rafts. 

Some species of sawflies glue their eggs to the surface rather than inserting them into the plant tissue.

Do They Bite or Sting?

Sawflies don’t usually pose a direct threat to humans as they cannot bite or sting. 

Despite their similarity to wasps, they do not have stingers, and their saw-like ovipositors aren’t as good weapons. 

For this reason, they’re also commonly known as “stingless wasps.”

sawfly
Elm Sawfly

Are They Poisonous or Venomous?

Sawfly larvae can secrete a distasteful and irritating liquid in self-defense to ward off predators. 

If you end up agitating them or making them feel threatened, they might squirt it on your skin or, worse, into your eyes.

Are They Harmful to Humans as Pests?

While not every sawfly species are equally harmful, many of them are major. Sawfly larvae can cause extensive damage to host plants by defoliating them and skeletonizing the leaves. 

Heavy sawfly infestations can also result in the death of the host plant or tree. 

Thankfully, there’s only one type of sawfly known to attack vegetable crops, and it only feeds on sweet potatoes.

Can They Come Inside Homes?

Sawflies don’t usually get indoors, and most of their preferred hosts aren’t houseplants. However, they might get in through open windows or doors. 

Especially if there are trees around your home, there’s a chance that sawflies or sawfly larvae infesting them might fall inside.

Elm Sawfly

What Are Sawflies Attracted To?

Naturally, sawflies are primarily attracted to their preferred host plants. While Both trees and shrubs are vulnerable to various sawfly species. 

If you have any potential host plants in your garden, you should watch out for sawflies in spring.

How To Get Rid of Sawflies?

Healthy and mature deciduous plants can usually survive sawfly infestations for a season.

Even if they get defoliated during a severe infestation, they can regrow the leaves.

However, even if a sawfly infestation doesn’t cause any lasting damage to your garden, sawfly damage can greatly lower the aesthetic appeal.

Effective ways to get rid of sawflies include:

Manual removal

If there’s just a small number of sawflies, you can remove them manually and kill them by putting them in a bucket of soapy water.

Spraying water

Simply spraying the infested plants with a high-pressure jet of water to knock off the pests should work too. However, take care not to damage delicate plants.

Natural predators

Attracting natural predators to your garden is a great way to keep pest populations under control. Parasitic wasps can help you get rid of sawfly larvae.

sawfly
Elm Sawfly

Low-impact insecticides

Before using chemical insecticides, try out low-impact options. Horticultural oils and insecticidal soaps are effective against young larvae and have minimal impact on beneficial species.

You may also use Spinosad and Azadirachtin for residual treatment.

Chemical insecticides

If the other methods fail to bear fruit or you need quick results, you may have to resort to chemical insecticides. 

A single treatment of contact residual insecticides like bifenthrin, permethrin, or carbaryl is usually enough. 

Alternatively, you may use systematic insecticides that transport through the plant tissues and kill larvae feeding on the leaves or cones.  

Frequently Asked Questions

Can sawflies hurt you?

When threatened or aggravated, sawflies secrete an irritable liquid during the larval stage. Apart from this, they aren’t capable of hurting you. 

Sawflies can’t bite humans, and unlike wasps, they lack stingers. As long as you don’t mishandle sawfly larvae, you usually need not worry about getting hurt.

Should I get rid of sawfly?

While sawflies are pests, you don’t always need to get rid of them. As long as your plants remain healthy and strong, they can usually withstand and survive sawflies. 

However, if it’s a large infestation or the sawfly species is known to cause heavy damage, you should work on eliminating them. 

What do sawfly larvae grow into?

Sawfly larvae grow into adult sawflies – insects belonging to the same order as wasps, ants, and bees. While some sawflies look like flies, many species closely resemble wasps. 

You are more likely to come across sawfly larvae than adult sawflies, as they live for a very short period as adults.

Is a sawfly a wasp?

Although sawflies are often mistaken as wasps or known as stingless wasps, they’re a completely different group of insects. 

Unlike wasps, sawflies don’t have stingers – they have a saw-like ovipositor instead that they use to insert eggs into plant tissue.

Wrap Up

Sawfly identification can be a little difficult due to the similarities they share with other insects. Many sawfly species are Batesian mimics and replicate the behavior of wasps to avoid predators. 

However, it’s the larvae that you need to get rid of, and hopefully, this article has been helpful in this regard.

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 – Dogwood Sawfly

 

White Caterpillar
Hello bug people,
I’ve had a great time looking at your site and your link to Bug Guide, but I didn’t find a match for these guys that have devoured my red twig dogwood seemingly overnight! It is September 15 in Ionia, NY—-that’s way upstate, south of Rochester and northwest of Canandaigua Lake. Most of them are the white ones, but a few are the black with white stripes. In the 18 years we’ve lived here, nothing has ever eaten this bush. Do you know what they are? And are they two instars of the same caterpillar. Are they good or bad? Thanksverymuchly,
Millie Sigle

Hi Millie,
You will never find your fascinating creatures on a caterpillar page unless they have been misidentified. These are actually Dogwood Sawflies, Macremphytus tarsatus. When we saw your subject line, we thought you might be sending us an image of the Cimbex Sawfly, but we were nicely surprised as this is a new species for our site. According to BugGuide: “Young larvae are covered with a powdery white waxy coating. Mature larvae are yellow beneath with black spots or cross-stripes above.” The Natural Land Trust website has a nice page devoted to the Dogwood Sawfly. Sawflies are related to wasps.

Letter 2 – Sawfly Metamorphosis

 

Nematus ribesii – Gooseberry Sawfly
Hello,
We really enjoy your site, it’s a great resource. My son and I have been looking at some caterpillars feeding on our Red Currant in Edmonton Alberta Canada.

They are voracious feeders, here are some pictures of the various stages from egg to larvae and adult.

We managed to grow some larvae to the adult stage which made the identification much easier. Would you agree that this is Nematus ribesii – Goosberry Sawfly?
John and Andrew Simon

Dear John and Andrew,
First, we want to praise you for your incredibly excellent documentation of this Sawfly Metamorphosis. What patience and diligence you have. We don’t disagree with your identification based on larval images found on the Down Garden Services website, but a real expert might have a definitive identification. A suspect adult image we located does not match your adult. Thanks ever so much for your contribution of, if not the metamorphosis of the Gooseberry Sawfly, Nematus ribesii, at least a closely related species.

Letter 3 – Striped Alder Sawfly

 

British Columbia South Coast
Found thousands and thousands of these caterpillars infesting a few Alder trees… they are everywhere! Haven’t seen any tents and the trees are now completely leafless. They are quite small, less than an inch in length. Have looked online to identify them, but no luck aside from the fact that I believe they are feeders! Any idea what kind they are?
Amelia

Hi Amelia,
We must begin with a compliment. Your request is so thorough and has allowed us to positively identify your insect in just a few minutes of web searching. You provided a location, a food plant and a photo. This is not a caterpillar. It is a Striped Alder Sawfly larva, Hemichroa crocea. The larvae are social feeders and BugGuide has an excellent image of a group feeding together.

Letter 4 – Sawfly

 


Hi there, we live in central/western Canada, and a friend of a friend found this fly on her peonys, I thought it might be a sawfly, but it looks as though it drinks nectar (by its long nose lol!) Any ideas? Thanks alot
Laurie Summers
Saskatchewan,Canada

Hi Laurie,
Definitely a Cimbex Sawfly.

Letter 5 – Probably Sawfly

 

do you recognize this insect?
Can you identify this insect? Does it bite? thanks

This appears to be a Cimbicid Sawfly, but the photo is so blurry we cannot be certain. You did not provide us with a location, but the file is labled “iron mountain fly”. We found an Iron Mountain, Michigan, but we are not certain that is where this photo was taken. Not providing us with helpful information combined with the blurry image makes this identification speculative guesswork. There is a genus of Sawflies, Trichiosoma, that has similar coloration. BugGuide has gotten specimens from Pennsylvania, and that is close to Michigan. Sawflies are nonstinging relatives of wasps. Some have powerful mandibles and can bite, but they are not poisonous.

Thanks much for solving the mystery. Yes, it was seen in Iron Mountain, Michigan. Sorry about the bluriness, it’s menacing appearance must have made my hands shaky.

Letter 6 – Cimbicid Sawfly

 

Scarab Hunter Wasp?
This guy was on one of our fenceposts earlier today. It looks like a Scarab Hunter Wasp although it has lobes on the end of it’s antennae which don’t seem to appear in any of the Scarab Hunter photos I’ve seen. If it is a Scarab Hunter I don’t believe it is supposed to be in our area (northwest Washington), is that correct? Do you agree that it is a Scarab Hunter Wasp? At the time of the photograph it was very lethargic and could only fly a few feet and then it would sit still until prodded. Thanks,
Bill Scollard
Granite Falls, Washington

Hi Bill,
This is actually a Cimbicid Sawfly. It is probably in the genus Cimbex. Sawflies are related to wasps, but they do not sting.

Letter 7 – Cimbex Sawfly

 

Caterpillar
I found this little guy on a tree in my yard late August. I’ve never been fond of the creepy crawlies, but I can appreciate a beauty like him. I’ve just found your website, and become rather infatuated with it. It’s quite impressive! He was found in southern West Virginia, about two inches long, completely hairless (I thought this notable, as all other caterpillars I had ever seen had much hair). I took a quick picture and played around with it. I hope it’s not too difficult to identify. I was too bugged out to get much closer. I’ve lived in West Virginia my whole life, but have never seen this species (although I don’t go outside much when the bugs are out). Could you help me out, please? Thanks Much!
Brandi

Hi Brandi,
This isn’t a caterpillar, but a Cimbex Sawfly Larva. The larva of this wasp relative is often mistaken for a caterpillar.

Letter 8 – Sawfly

 

Unknown fliers
Hi Daniel,
Glad to hear that you’re up and running. I’ve taken a few shots of some flying insects that I’m unable to identify. You’re help is, as always, greatly appreciated. We found the first fly on the side of our pool. I’ve looked through your fly pages, and haven’t been able to find any matches to the first two fly pictures I’ve sent.
Thanks again!
Yvonne
Barrie, Ontario

Hi Yvonne,
Flies have just two wings. We are requesting Eric Eaton’s assistance with this Hymenopteran. Here is what Eric has to say: “The specimen in question is a sawfly, and it looks to be in the family Argidae, if the last antennal segment is very long, as it appears here. Argids include one recently-introduced species currently found ONLY in Ontario, and this may be it. Would like to have the submitter post it to Bugguide as well, if possible. Thank you. Eric”

Letter 9 – Cimbex Sawfly

 

Cimbex in Quebec Canada
Hello.
Hi, we found this in Quebec; it’s a huge and beautiful fly no!
Philippe de France

Hi Philippe,
Your Cimbex Sawfly is beautiful. Thank you for resending it as we were unable to open your first attachment.

Letter 10 – Cimbex Sawfly

 

Cimbex Sawfly
Hi, found this huge Wasp/Hornet(We thought at the time) and took some photos of it. Was able to identify it as a Cimbex Sawfly because of your site so I thought I’d send you a few of them. Found Sunday, June 18/2006 at about 8:00pm. Great site,
Thanks.
Andy Kowalski

Hi Andy,
Thanks for sending in your image of a Cimbex Sawfly. The clubbed antennae are a distinguishing feature.

Letter 11 – Italian Sawflies

 

Apple green caterpillar with yellow dorsal and black spinacles
Hi,
I live in Milan and have a rose creeper on my balcony that has recently become the home for 25+ caterpillars. I have been searching around but I have yet to find out what they are. Your site’s excellent and seems to have everything so I’ve probably just missed it somewhere. Please could you take a look and let me know what you think they might be?
Many thanks!
Lucy

Hi Lucy,
These are not caterpillars which metamorphose into butterflies or moths. These are wasp relatives known as Sawflies. Sorry, can’t tell you the species.

Letter 12 – Tremex columba

 

Pigeon Horntail
Hi WTB…
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.

Letter 13 – Cimbex Sawfly

 

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!!
Jen

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.

Letter 14 – Sawfly

 

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!
Roger

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.
Eric"
Sawflies are related to ants, bees and wasps, belonging to the order Hymenoptera. Larva of most species feed on foilage. They do not sting.

Letter 15 – Cimbex americana, possibly

 

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.

Letter 16 – Elm Sawfly

 

Caterpillar @ Presque Isle River
Seen: Presque Isle River in MI’s U.P. I did not see this on your site.

You couldn’t locate this “caterpillar” because it is not a caterpillar. It is an Elm Sawfly Larva, Cimbex americana, which can be found on Bugguide.

Letter 17 – Club-Horned Sawfly from UK

 

What is this bee like insect with club antennae
Found today Doncaster UK. Is this a bee or a mimic ( has mandibles and unusual club ended antennae) ? Many thanks
Gerry Collins

Hi Gerry,
This is a Club-Horned Sawfly in the family Cimbicidae. Cimbicid Sawflies are related to both bees and wasps, and they do not sting. The larvae look like caterpillars and they are frequently mistaken for them.

Letter 18 – Introduced European Saw Flies in Washington???

 

Please help us if you can!
I live in a condo association. Today we discovered these insects in several of our small pine cone bushes. There are hundreds and hundreds of them in all the bushes. If you could identify this caterpillar or worm I would VERY much appreciate it. Most of them are totally black and smoth and slimy like a snake and about 1 inch in length. Here is a picture: Looking forward to a reply at your earliest convenience! Thank you so much!
Gail Phillips
Bellingham, Washington

Hi Gail,
We believe you need to contact your local Department of Agriculture Insect Pest Control division. Call 360-902-2070 or email PestProgram@agr.wa.gov because we believe you have the Introduced European Saw Fly, Diprion similis. This introduced species is known in the eastern U.S., but we cannot find any indication that it has become established in Washington. BugGuide reports it as far west as Wisconsin. If you have an isolated outbreak, control might still be possible. The University of Georgia Forest Pests website indicates: “The introduced pine sawfly occurs from Canada to North Carolina, and in the central and lake states. Eastern white pine is its favored host, but it also attacks Scotch, red,jack, and Swiss mountain pines. Infestations of this insect can be very serious in young plantations of white pine grown for timber products or Christmas trees.” Several days ago we received a letter from Michigan regarding this species.

Probable Confirmation: (06/02/2008) Sawfly larvae on Whatcom pines
Hi Gail (and others )
The larvae are likely the European pine sawfly, and yes, the occurrence of the species is the first for Washington State (and Western U.S.). However, the species has been in neighboring British Columbia, Canada, for some time, including areas of the Frasier River delta which is not far from the Bellingham area. Here is a link to information on the B.C. occurrence: http://www.pfc.forestry.ca/entomology/defoliators/conifer_sawflies/european_pine_e.html I appreciate your interest and efforts to bring the situation to our attention. I am in the process of getting some of the larvae (with help from the County Extension office) to get confirmation of the species and would be glad to let you know if/when that happens. Thanks again for the contact.
Eric LaGasa
Chief Entomologist
Pest Program / Plant Protection Division
Washington State Department of Agriculture
lagasa@agr.wa.gov

Eric,
Thanks so much for your Email and information contained therein regarding our occurrence of this recent troubling ‘event’. Yes, we would very much be interested in continuing updates regarding this ‘infestation’. Also, many thanks to whatsthatbug.com for their immediate response to my inquiry in helping to identify this particular species! Sincerely,
Gail Phillips

Ed. Note: The spread of the European Pine Sawfly can be a threat to our Western logging industry as the species is proliferating without natural predators.

Letter 19 – European Pine Sawflies

 

This worm is destroying my evergreen shrub
Hi Bugman!
My son found these tiny inchworm-like things on our evergreen shrub today (We live in Michigan). They were in a tight cluster of about 100 worms, each about an inch long. They have tiny, shiny black ball-like heads. In the photo they look hairy, but they aren’t. They are smooth and green all over, with no other markings at all. Upon further inspection, we found several branches of the shrub covered with these things. Several areas of the shrub have been stripped clean of needles, and there are several dying branches as well. At regular intervals (about every 10 seconds) EVERY SINGLE worm on the branch bends straight up, very quickly and in UNISON. It’s quite bizarre to watch. I did check out all of the caterpillar photos on your site, and as a result I ended up looking at Giant Gypsy Moths, Army Worms and Eastern Tent Worms, but none of those look quite like these. I’d say they look most like the Eastern Tent Worm, but there is absolutely no evidence of any tenting or any other type of shelter being formed. Perhaps I just caught them at a very early stage, prior to tent construction? Sorry, these were the best photos I could get. What do I do? They are making short work of my large shrub, and I fear that they will move onto the flowers and vegetables next… Many thanks,
Terri

I think I found it! I believe them to be European Pine Sawflies.
http://woodypestguide.cas.psu.edu/132.htm Now how to get them away from my pine…?

hi Terri,
Once we darkened and sharpened your image, we believe you are correct in your identification of the European Pine Sawfly, Neodiprion sertifer. Your excellent verbal description of their behavior supports the identification. There is an excellent image on BugGuide. There is no danger of them moving to your other plants as most insects are somewhat host specific. You can try hand picking the culprits.

Letter 20 – Elm Sawfly

 

Some sort of bee?
Hey guys great site!! I’ve got a picture of some sort of bee, or maybe a fly, that landed on me last summer while I was camping in Maine, around the Katahdin area. It was probably about 3/4" long, all black with three white spots on either side and some white between the head and abdomen. I had fun observing him while he crawled around on my hand; he stayed there for quite a while. I looked on every bee and fly page on the site, but didn’t find anything that looked like my little friend. Can you help me? Thanks!
Mischa

Hi Mischa,
What a nice photo of an Elm Sawfly, Cimbex americana. The Elm Sawfly is related to bees and wasps, but does not sting. Its larva looks somewhat like a caterpillar.

Letter 21 – Ichnuemon or Sawfly? Nope: Leucospis species

 

Nifty Ichneumon, But Which One?
This little cutie is drilling into my Mason Bee habitats. The block is Douglas-fir, the step shown is about 1/8". She was busy that day, I probably lost many bee larvae but she was delightful to observe. I would be interested in an ID, have not found this particular species in any of my books.
Steve Cameron

Hi Steve,
We would love to know where you are located. How big is the specimen? We are trying to research exactly what she is and the information would be helpful.

Hey, thanks for the rapid reply! These pictures were taken in Portland, OR, USA. My back yard; partially shaded by 2 fruit trees. Many plants native to this area in yard. Small pond within 5 meters of picture location. Subject was about 13 mm to 15 mm, as I recollect. The block that she is working on is a 4×6, or 31

Letter 22 – Army Worms in Ecuador probably Sawflies

 

Group locomotion
Hi,
I saw this on the western andean slopes in Ecuador – fascinating! But what is it?
Thanks,
Hugh

Hi Hugh,
Caterpillars that move in this manner are generally referred to as Army Worms. They travel in a mass to the next source of food.

Update:  March 26, 2016
We just received a comment indicating these look more like Sawfly larvae.  Looking closely at this nine year old posting, and considering what we have learned since then, we are in agreement.

Letter 23 – Introduced Pine Sawfly

 

Caterpillar ID please!
Hello Bugman.
Would love it if you could help me id this beauty. I found her in the garden in Chelsea, QC. Isn’t she stunning?
Thanks for your help!
Celine
Québec, Canada
Much appreciated

Introduced Pine Sawfly
Introduced Pine Sawfly

Hi Celine,
This isn’t a caterpillar. It is a Sawfly Larva, a relative of wasps. We believe it is the Introduced Pine Sawfly, Diprion similis. According to BugGuide, the species was “First recorded in Canada in 1931 near Oakville, Ontario, and has not spread naturally much beyond there. There were light infestations in other parts of Ontario in the 1970s and one in southern Quebec in 1940. “

Letter 24 – Poison Ivy Sawfly

 

colorful sawfly larva
Tue, Dec 23, 2008 at 10:49 AM
Hi WTB,
I took these photos more than two decades ago in Rhode Island, near an old lime kiln (I was looking for land snails). I always thought this was a caterpillar, but recently when I couldn’t find it in Caterpillars of Eastern North America, I was perplexed. I e-mailed the author of that book, David Wagner, and sent him these photos. He identified it as the poison-ivy-eating sawfly larva. I search the WTB pages and could not find this sawfly larva pictured, so I thought perhaps you would like it.
Keep up the good bug work!
Jeannie
Rhode Island

Poison Ivy Sawfly
Poison Ivy Sawfly

Hi Jeannie,
Long ago we posted an image of an unidentified Sawfly that looked similar. Thanks for sending your photo of a Poison Ivy Sawfly. Out of curiosity, do you have a scientific name?  We did a web search of Poison Ivy Sawfly and found Arge humeralis.  There is a matching image on BugGuide.  We searched our archives for the image we posted in 2007, and sure enough, it was found on Poison Ivy.

Letter 25 – Skeletonizing Leaf Beetle Larvae, NOT Unknown Sawflies on Coyote Brush

 

caterpillars in coyote brush (Baccharis pilularis) in Carpinteria, CA
Tue, Mar 31, 2009 at 9:38 PM
I’m not sure what these green caterpillars are. There were hundreds of them in the Coyote Brush (Baccharis pilularis) at the Carpinteria Salt Marsh Nature Park this past weekend.
John Callender
Carpinteria Salt Marsh Nature Park, Carpinteria, CA

Unknown Sawfly on Baccharis
Skeletonizing Leaf Beetle Larvae on Baccharis

Hi John,
We will check with Eric Eaton, but we believe these are Sawflies and not Caterpillars. Sawflies are the larval form of a non-stinging member of the order of insects that includes ant, bees and wasps, Hymenoptera.

Update:
Daniel:
Hard to tell from the image, but either sawfly larvae or chrysomelid leaf beetle larvae.
Eric

Update: May 29, 2011
Upon searching for the identity of a Skeletonizing Leaf Beetle on BugGuide, we discovered that these are the larvae of
Trirhabda flavolimbata.

Letter 26 – Sawfly

 

No idea what this is.
July 12, 2009
Found this while walking down a walking path in Calgary in July. Can u tell me what it is?
Lynne
Calgary, Ab

Sawfly
Sawfly

Hi Lynne,
It is a Sawfly in the genus Cimbex.  We found one unidentified species from California that resembles your rusty colored individual, but the angle of the photo does not allow us to view anatomical details that would make a more definite ID possible.
Sawflies are non-stinging relatives of wasps.

Letter 27 – Cimbicid Sawfly

 

Glacier Bee/wasp?
July 13, 2009
Hi there, I’m Shannon from Alaska. I took my friend hiking on Byron Glacier today and found a bee like creature… on the ice! I wasn’t sure at first if he melted out of there or was taking a rest but I’ve never seen anything like him around here. I was hoping you could help?
Shannon from Alaska
Byron Glacier/Portage Alaska

probably Elm Sawfly
Sawfly

Hi Shannon,
Mistaking this Sawfly for a Bee or Wasp is understandable since Bees, Wasps and Sawflies are all in the same order of insects, Hymenoptera.  Sawflies do not sting.  We cannot say for sure what species or even what genus your specimen belongs to, but we are confident it is one of the Cimbicid Sawflies in the family Cimbicidae.  According to BugGuide:  “Adults robust, resemble bumble bees. Base of abdomen broadly joined to thorax (no wasp waist). Antennae have seven or fewer segments, slightly clubbed.
”  Your specimen is robust and has clubbed antennae.  The larvae of Cimbicid Sawflies are often confused with caterpillars because of their appearance and because they feed on foliage. BugGuide lists three genera in the family, and all are represented in the western portion of Canada.  At first we thought this might be an Elm Sawfly which is reported from Canada, but now, because all the examples of Elm Sawflies on BugGuide show yellow antennae, we believe this might be a Honeysuckle Sawfly, Trichiosoma triangulum, and BugGuide has an image posted from Montana that looks very similar.

Update from Eric Eaton
Daniel:
The sawfly with the cigarette lighter is, besides causing trouble (ha!), probably Cimbex pacifica.
Eric

Letter 28 – Elm Sawfly

 

elm sawfly and grapevine beetle
July 14, 2009
Hi Bugman!
Just used your site to identify this Elm Sawfly I saw while hiking in the mountains of North Carolina. Thought you might like the photo.
I also was able to identify the cute little Grapevine Beetle that was sadly squished on the grill of my car. Sorry little guy!
Carrie
North Carolina

Elm Sawfly
Elm Sawfly

Hi Carrie,
We are happy that our site was helpful.  We are posting your two images separately since combining postings with unrelated subjects tends to compromise our already questionable archive organization.  The Elm Sawfly, Cimbex americana, is an impressive creature.

Letter 29 – Elm Sawfly

 

Large Black Fly
July 30, 2009
Hello!
My sister-in-law found this critter as it tried to take a short rest on her shoulder. We didn’t get a very good picture of it, but to be honest everyone was kinda scared of it! He is about 1.5 to 2 inches long, which makes it the largest fly I’ve ever seen in this area. The location is northern New Hampshire, and this was in late July.
I did a bunch of research online, but it doesn’t match anything I can find. The split-wing and yellow stripe are what seems to be throwing me off. He has a head that looks more like a hornet than a fly, but no stinger.
Hope you can help, and thanks for your time!
Tristan
Littleton, NH

Elm Sawfly
Elm Sawfly

Hi Tristan,
The reason this Elm Sawfly has a head that looks like a wasp is that they Sawfly is in the same order of insects as Wasps, Hymenoptera.  Flies only have two wings.  You may read more about Elm Sawflies on BugGuide.

Letter 30 – Unknown Irish Insect is Transparent Burnet

 

Irish invasion
August 9, 2009
Enjoying a walk on Isis Mor in the Tri-Island Aran Islands I beleive I was bitten by this strange insect, the bite developed into a sunken bruise and I have since recovered but I would very much like to know what it was. and also what you would recommend for me to read as Entomology is a fascinating field, specifically books that help in the identification of insects.
Thank you for your assistance!
Tómas Ó Gallachóir
Éire

Unknown Irish Insect:  Owlfly perhaps???
Transparent Burnet

Hi Tómas,
This is a mystery and your photo doesn’t show the type of detail we would like to see.  Our first guess, would be a  Lepidopteran, and then an Owlfly in the family Ascalaphidae, but we cannot seem to locate anything that remotely resembles your insect online.  The clubbed antennae and wings lead us to believe this is either an Owlfly or a member of the order Lepidoptera (butterflies and moths).  Is it possible the bite you describe came from another insect?  It is possible an Owlfly might bite, but we can’t image the bite reaction you describe.  This might also be a Sawfly, but again we are really puzzled by this challenging identificaton.  We are going to enlist some assistance in this identification.

Update from Eric Eaton
Hi, Daniel:
It is a moth, specifically the “transparent burnet,” Zygaena purpuralis.  Seriously doubt it is capable of “biting” with its proboscis.
Eric

Thanks Eric,
We are linking to the UK Moths page on the Transparent Burnet.

Thanks for the update Eric and Daniel, I’m glad it proved a challenge to identify! I am not 100% it was this nearby ”Ztgaena Purpuralis” that was the culprit in the biting, As I reflexively brushed the insect that bit me away without getting a good look at it, I just presumed that it was this guy as he was nearby and slightly resembled what had bit me, in proportions anyway, although the wings of the biting insect could have been more green/grey in colour.
Thanks again
Tómas

Letter 31 – Dogwood Sawflies

 

What’s that caterpillar?
August 14, 2009
Hi —
I love your site and browse it for pleasure when I have time. One damp, overcast morning in August I found an outbreak of these caterpillars on the leaves of my red-bark dogwood shrubs. We live outside of Philadelphia, PA and have had an incredibly wet summer. Any ideas?
Thanks!
Betsy
Merion Station, PA

Dogwood Sawfly Larvae
Dogwood Sawfly Larvae

Hi Betsy,
These are not Caterpillars, but that is a very easy mistake to make.  These are the larvae of Dogwood Sawflies in the genus Macremphytus.  We are linking to a matching photo on BugGuidePenn State Woody Ornamental Integrated Pest Management website has a wonderful explanation of the life cycle of the Dogwood Sawfly.  It states:  “Dogwood Sawfly, Macremphytus tarsatus, is a significant pest to dogwood (Cornus) species. Because the Dogwood Sawfly takes on several forms while in the larval stage, it may not be easy to identify. Even the first instars can devour small portions of leaves, with groups of them producing a skeletonized appearance to the leaves. However, the larger final instar can consume entire leaves, leaving only the tougher leaf midribs.”

Letter 32 – Argid Sawfly, but what species???

 

sawfly larvae on hazelnut leaf
August 20, 2009
Hi WTB, I found these creepy caterpillars chomping on my contorted hazelnut. Finally determined that they are sawfly larvae but can’t find an exact match on your site. They look like they are made of green jello – yuk! Any idea what species they might be? Thanks for all your help and for maintaining such a great site!!!
Laura
Southeast PA, north of Philadelphia

Sawfly Larvae on Hazelnut
Sawfly Larvae on Hazelnut

Hi Laura,
We agree that this is an Argid Sawfly in the family Argidae.  According to BugGuide, the Birch Sawfly, Arge pectoralis, feeds on Hazelnut as well as birch and other trees, but the larvae have orange heads and the heads on your individuals are black.  We are pretty confident the genus is Arge, but we will have to postpone exact species identification.

Sawfly Larvae on Hazelnut
Sawfly Larvae on Hazelnut

Letter 33 – Argid Sawfly

 

Giant orange caterpillar
August 29, 2009
Can you identify this caterpillar? Seen in eastern PA on a canal towpath in August, length about 4″, width over .5″.
Elissa
Bethlehem PA

Argid Sawfly Larva
Argid Sawfly Larva

Dear Elissa,
Unless this is an irradiated mutant, we doubt that the Argid Sawfly Larva you found was 4 inches long.  Argid Sawflies are not Caterpillars, but are non-stinging relatives of wasps.  We cannot tell you the exact species, but we are linking to an image on bugguide that looks similar to your example.

Letter 34 – Leaf Skeletonizer Moth on Euonymus

 

What is this Orange, Yellow, Black bug?
October 31, 2009
Flying insect found in Anne Arundel County, MD. Size =0.75 inch. Wing span compact (delta shape) about 1.25 inches when extended. Dark wing veins. Head and feet black. Abdomen yellow/orange and appears “fuzzy”.
Currently swarming. Swarms appear to be mating and are found on top branches of euonymus bushes (our Burning Bush was decimated by caterpillars this spring, could this be the same insect?). Never seen this variety of bug in past 12 years in this area.
Peter
Anne Arundel County, MD 21146

Unknown Sawfly? or Moth???
Unknown Sawfly? or Moth???:  Leaf Skeletonizer Moth

Hi Peter,
We really wish your photograph was of a higher resolution as it is impossible to make out any details on your infestation.  We found information on a Euonymus Caterpillar, Yponomeuta cagnagella, but the photos of the moths on BugGuide look nothing like your insect.  We also located a pdf (euonymus_A3633) on the same species.  We believe your insects look like Sawflies, but again, there isn’t much detail.  We have not had any success locating information on a Sawfly that uses Euonymus as a host plant.  If there was a caterpillar invasion in the spring, and sawfly larvae are often confused for caterpillars, we suspect these adults might be related.  We would not rule out moths, but we suspect these are Sawflies.  Perhaps one of our readers will be able to assist in a proper identification.

Unknown Sawfly? or Moth???
Unknown Sawfly? or Moth???:  Leaf Skeletonizer Moth

Eric Eaton Responds:
Oh, man….My first thought is “aphids,” actually, or maybe psyllids?  Might try sending this to the Ent Dept. at University of Maryland in College Park.  They will probably recognize it right off….
Eric

Bagworm Moth Perhaps
Leaf Skeletonizer Moth Perhaps

Our identification request:
Dear Drs. Mitter, Kent and/or Hawthorne,
My name is Daniel Marlos and I run the highly unscientific, pop culture, insect identification website What’s That Bug? at www.whatsthatbug.com on the web.  Today I received an image from Maryland that has me perplexed.  I thought perhaps a sawfly or even a moth like a Bagworm.  Eric Eaton has suggested possibly an Aphid or a Psyllid.  The insect is swarming on Euonymus and there were caterpillars on the same plant in the spring.  Can anyone provide an identification?  I realize the photo is of very low resolution.
Thanks for your time.  Here is a link to the posting:  2009/11/02/sawfly-on-euonymus-we-believe/
Daniel Marlos

Bagworm Moths Maybe

Daniel,
Thanks for the reply.  I’ll have to work on getting a camera that can do close-ups.  I looked at the sawfly photos on Google images- not even close. The bugs in my yard have dark heads (black) and fuzzy (furry) bodies.  No saw extending out the back of abdomen.
The antenna are very long and branching like those of a moth.
The head and legs are black.  The wings translucent with black veins and a black hue. The abdomen is bright yellow-orange and fuzzy.
I’ve tried to take some additional photos (bugs out side are rather sluggish in the cool weather), but I still lack close-up lens to really get detail.  I’ll send these in separate e-mails since they are rather large.
Look forward any further thoughts you may have.  They are a very unusual and quiet beautiful bug….
Peter

Unknown Moth on Euonymus
Leaf Skeletonizer Moth on Euonymus

Thanks Peter,
The new photos are so much better.

Identified by Edna
NAKED see this
now that i have your attention..here is a link to those things you wanted to know what are from anne arundal county,,,that eric eaton thought could be aphids
they are something new! an introduced species of leaf skeletonizer moths..
http://bugguide.net/node/view/155100#205755
also would you like some photos of the sequoie sphinx larve, or a nice shot of elegant sphinx larve , ash sphinx  for your sphinx pages? if so let me know..
Edna

Letter 35 – Seagrape Sawfly from Honduras

 

Possible sawfly laying eggs
November 4, 2009
I was encouraged by Eric Eaton (Kaufman Field Guide to Insects of North America) to forward my question and photo to you for help in identification. He indicates that the insect is not a cicada, but is most likely a sawfly of some type. Thank you in advance for any guidance you can give!

My original question to him:
On September 8, 2007 I noted this (and numerous other identical) insects all laying eggs in similar clusters on the underside of leaves on a small tree. The tree had somewhat leathery leaves… perhaps a ficus of some sort? The location was within 100 feet of the ocean on the west end of the Honduran island of Roatan. I initially thought the insect was a type of fly – but am now convinced it is a cicada of some type. It seems to be morphologically similar to the Emerald cicada, Zammara smaragdina, from Honduras – photo at this site:
http://nathistoc.bio.uci.edu/Honduras/Hemiptera/Zammara%20smaragdina.htm
Over the last two years, I have contacted a series of individuals looking for help with ID, to no avail. Can you help?
Karen
West End of Roatan Island, Honduras

Unknown Insect lays eggs
Seagrape Sawfly lays eggs

Dear Karen,
First, let us say that your photograph is lovely, and the insect is an interesting specimen.  We are quite intrigued that Eric Eaton referred you to us since we constantly depend upon Eric to make corrections for us.  We do have several contributors who love the challenge of identifying exotic species that we post, and we hope Karl is reading.  Our first thought is that this might be a Free Living Hemipteran in the suborder Auchenorrhyncha, which includes the Cicadas.  Eric Eaton has pointed out in the past that there are many exotic families found in the tropics that are not represented in temperate areas.  If Eric believes this is a Sawfly, we do not want to disagree.  We would strongly recommend that you provide a comment to our posting so that if six months down the line, your insect gets identified, you will be notified.  We do not maintain a database of email addresses for our readership, and though we send emails directly at the time of posting, once time has elapsed, we would not be notifying the querant directly. We would also inquire if you have any images showing the head of the insect as that might help to narrow the field of suspects.

Thank you for your comments.  With the help of both Eric Eaton and Dave Smith (research entomologist retired from the Smithsonian), I now have the identification for this sawfly.  Here is Dave Smith’s comment:
Argidae:  A sawfly, Sericoceros mexicanus (Kirby). For a good article on this, see:
Ciesla, W. M. 2002. Observations on the life history and habits of a tropical sawfly, Sericoceros mexicanus (Kirby) (Hymenoptera: Argidae) on Roatan Island, Honduras. The Forestry Chronicle 78(4): 515-521.
The plant must be seagrape, Coccoloba uvifera. Females lay eggs in clusters on the leaf, and stand guard over the eggs until they die. Larvae feed on the leaf edges. Sericoceros mexicanus occurs from southern Mexico to Panama. Other species of the genus are found from Mexico to S. Amer. and in Puerto Rico.

Once we had a name, finding more images online was easy.

Letter 36 – Elm Sawfly

 

hairless bumble bee?
April 18, 2010
Dear Bugman,
I have been collecting insects for about 9 years. I have been able to identify all of them except for this one. I found it on a log , and when I went to catch it, it did not try to fly away.
Aaron
Sullivan county, Pa

Elm Sawfly

Hi Aaron,
You have been having difficulty with your identification because this is not a Bumble Bee.  It is an Elm Sawfly, Cimbex americana, the largest North American Sawfly.

Letter 37 – False Pine Webworm

 

Infesting my mugo pine
April 23, 2010
April, 23, 2010 – I live in Toronto, ON Last week I notice bunch of flying bugs in my mugo pine, after careful examination I realised that they were all over the mugo. They like to get right into the pine needles and escially where the new candles are growing. When they fly the wings make a buzzing sound, they can be easily swatted away. I don’t want to lose my pine and was wondering how I could enticed them to move. I did my best with the attached picture it shows both the red-headed one and the black one. You insight is greatly appreciated.
TD in Toronto
Toronto, Ontario Canada

False Pine Webworm

Dear TD,
We thought your insect resembled a Sawfly, so we searched through BugGuide and quickly found the False Pine Webworm, Acantholyda erythrocephala.  The female has a reddish orange head and the male is black with a yellow face, a sexual dimorphism that is clearly represented on your photograph.  BugGuide also indicates it is a:  “Serious problem on white pine along east coast of U.S. Also in Ont, Alberta and Newfoundland. Introduced from Europe in 1925.
”  Though they are not mating, we are going to tag your image as Bug Love nonetheless.

Letter 38 – Large Rose Sawflies from UK

 

A fly of about 1 cm. Bright yellow abdomen, brownish clear wings, slightly back curving antenae
June 5, 2010
On a rose bush in southern UK. A warm day, no wind. stayed on bush al day, gone at sundown – all three, see images
Richard Avery
Salisbury, Southern UK

Large Rose Sawflies

Hi Richard,
These are actually Sawflies, nonstinging relatives of wasps whose larvae often resemble caterpillars and when numerous, they are capable of defoliating trees and shrubs.  We don’t recognize this species and we will do some research to properly identify it.  The Bugs and Weeds website does not picture this species.

Daniel, Whoa, that was quick. I’ll wait for your species id. Thanks.
Richard

Daniel,
Now you have given me the heads up on sawflies I have investigated further and discovered it is ‘Arge pagana’ , the Large Rose Sawfly. Seeing the speckled larvae was an ‘Oh, right!!’ moment as I had seen them many times on my roses and never got around to identifying them.
Many thanks for your prompt and accurate info, guys like you make life so good!
regards from the UK
Richard

Hi again Richard,
We are glad we could help.  Thanks so much for writing back with the species name Arge pagana for the Large Rose Sawfly.  The Garden Safari website has excellent information on the Large Rose Sawfly.

Update:  July 27, 2014
Subject: Large Rose Sawfly
July 27, 2014 7:23 am
Thank you very much for identifying this bug for us. We found a few on our rose bush AFTER several leaves had been munched by what looked like caterpillars but which we now know are Sawfly larvae. Knowledge is power! Thank you again. Jen Murray, Biggin Hill, (southern) England, UK
Signature: Jen Murray

Letter 39 – Large Rose Sawfly

 

Yellow Fly
June 12, 2010
Hi, I have found half a dozen of these bright yellow flies on my rose bush. They are just sitting upside down on the stems. The fly is about 1/2 inch long. I have never seen this fly before do you have any ideas? I live in East Anglia in England and it is a lovely summers day. I hope the pics are good enough for you to identify! By the way I love your site. 🙂
Tanya
England

Large Rose Sawfly

Hi Tanya,
This was a very easy ID for us, because last week we received a photo of the same species from UK.  We knew it was a Sawfly, but we were not sure of the species.  Once we provided the querant, Richard Avery, with that information, he wrote back with a species identification of Arge pagana, the Large Rose Sawfly.

Hi Daniel,
Thank you very much for your reply and link to Richard’s query.  I hope they wont cause too much damage to my roses!
Many thanks
Tanya

Letter 40 – Giant Wood Wasp

 

wood wasp?
Location:  South Central Montana
August 27, 2010 6:55 pm
OK, Riddle me this Batman, what looks just like a Horntail Wood Wasp but has no antennae? Instead it has a long probiscus like a moth. My friend found it walking on a pine log in a wooded area.
Tanya in Montana

Wood Wasp

a bug just sent you for id
August 27, 2010 7:08 pm
Dear WTB I just not 10 minutes ago sent you 3 pictures of a wood wasp that wasn’t a wood wasp, as it has no antennae. Guess what? It’s a wood wasp! My friend caught it for me in a powerade bottle, and the antennae were glued together. I put it under a microscope to look more closely, and my husband said “Hey, they are just stuck together!”  Silly me, I’m sorry for wasting you time when there are REAL bugs that need identification! 🙂 Carry on with the amazing job you do. You are my favorite website.
Tanya in Montana

Hi Tanya,
Your series of emails amused us.  We believe you may have an image of the introduced Wood Wasp,
Urocerus gigas.  According to BugGuide and other websites, the introduced Giant Woodwasp:  “tunnels in wood. One of the most dangerous pests of conifers.

You guys are amazing! Just finding other people that love bugs like I do is so great. I hated to write in because I can only imagine how busy you all are. Thank you so much for taking time to answer my emails. sniff sniff I love you guys! 😀

Eric Eaton responds
Daniel:
Well, the scientific name, Urocerus gigas, is correct for the image, but I’ve never heard of it called the “Introduced Wood Wasp.”  My belief was that it is simply a “holarctic” species (meaning it is native to the entire northern hemisphere).
Eric

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Sawflies

Related Posts

17 Comments. Leave new

  • I definitely have these in my yard also! They are swarming all over, but they seem to hang out around this one bush I have and my porch, mostly. I’ve never seen them before this year (in Anne Arundel County too). I’m interested in seeing what anyone comes up with for this, because they are everywhere.

    Reply
  • Thank you for your comments. With the help of both Eric Eaton and Dave Smith (research entomologist retired from the Smithsonian), I now have the identification for this sawfly. Here is Dave Smith’s comment:

    Argidae: A sawfly, Sericoceros mexicanus (Kirby). For a good article on this, see:
    Ciesla, W. M. 2002. Observations on the life history and habits of a tropical sawfly, Sericoceros mexicanus (Kirby) (Hymenoptera: Argidae) on Roatan Island, Honduras. The Forestry Chronicle 78(4): 515-521.
    The plant must be seagrape, Coccoloba uvifera. Females lay eggs in clusters on the leaf, and stand guard over the eggs until they die. Larvae feed on the leaf edges. Sericoceros mexicanus occurs from southern Mexico to Panama. Other species of the genus are found from Mexico to S. Amer. and in Puerto Rico.

    Reply
  • I have these same bugs hanging around the shrub by my front door. I also live in Anne Arundel County. Are they dangerous? I can’t seem to find any information on them online. Above it says it’s a new species. Could we get some more information about them?
    Thanks,
    kellyjr05

    Reply
  • I have these on my roses in Sussex. They lay eggs in the stem of the rose and then all the little larvae eat my rose leaves and buds 🙁

    Reply
  • Audible Silence
    July 1, 2015 10:57 am

    Am currently trying to deter Large Saw Fly larvae from trashing my most treasured rosebush by squirting them and the bush liberally with washing up liquid and water mix – if it doesn’t kill them at least Hopefully it’ll give them a bad stomach ache!! 🙁

    Reply
  • How do I get rid of the sawflies the are eating all the new shoots on my penny lane rose?

    Reply
  • Hi folks,

    Those actually look a bit like sawfly larvae rather than caterpillars. It’s hard to tell with the photo resolution, but there are some social sawflies that move in groups like this…
    Cheers,
    Bill

    Reply
    • Thanks for providing a correction on this nine year old posting. Looking closely, we believe you are correct. We have updated the posting.

      Reply
  • Hi folks,

    Those actually look a bit like sawfly larvae rather than caterpillars. It’s hard to tell with the photo resolution, but there are some social sawflies that move in groups like this…
    Cheers,
    Bill

    Reply
  • This is first time I’ve spotted this insect on my roses, they sting new , healthy shoots ! are they leaying eggs ? they make lots of damage:( help!!!!!
    I live south east of England
    Roza

    Reply
    • It seems like your observation is correct.

      Reply
    • Clive Avery
      June 2, 2018 2:19 pm

      Interestingly I’ve just seen these for the first time on my roses- it looks like it might be a “good” year for them. From other sources it seems they “saw” a track in the young stem and lay eggs in the track, and the larvae when they hatch eat the rose leaves before pupating for next year. Apparently doesn’t usually do huge damage to the plant unless there’s a big infestation but it’s the larvae you need to deal with, not the females laying the eggs. I guess you could cut off the stems affected or deal with the larvae as they emerge.

      Reply
  • This is first time I’ve spotted this insect on my roses, they sting new , healthy shoots ! are they leaying eggs ? they make lots of damage:( help!!!!!
    I live south east of England
    Roza

    Reply
  • I’ve just dealt with two of these on my brand new (and very healthy) Pilgrim rose. Never seen them before (I’m in Shropshire, by the way) so I’m very grateful to your website for identifying them.

    Reply
  • I found two on my rose bush today. I’ve never seen them before either (I”m in North Hampshire) They took a bit of dislodging, leaving a track behind. I’m also grateful for your identification of them. How long are they usually a problem for? (Weeks/months, in warmer weather?) Does anyone have any recommendations for deterrents or treatment?

    Reply
  • I have never seen these fly’s before either i noticed them last week, on my climbing rose bush, i knocked them off with a lolly-pop tick as they seemed to be stuck on the rose bush stem, i wondered what was eating my young shoots in such away, what do you do to get rid of them??? i live in Manchester

    Reply
    • Annette Wilson
      May 26, 2020 5:36 am

      I seem to have a swarm of them in my new garden. But there are no damaged roses. Could it be something else?

      Reply

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