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

Subject:  Unknown Pinkish Caterpillar
Geographic location of the bug:  Motley, MN on a 22acre island on Lake Shamineau
Date: 08/17/2019
Time: 11:06 PM EDT
Your letter to the bugman:  Dear Bugman,
My sons and I were on a Father/Son retreat and we discovered this pinkish caterpillar w/ one long black strip down its back from its head to its rear-end.  It also had several black stripes that ran perpendicular to its one long black stripe.  The total caterpillar length was roughly 1 and 3/4 inch in length.  We know that their are likely many undiscovered insects and maybe caterpillars.  We’re wondering if the caterpillar we discovered on a small tree branch is already identified as we could not find it when searching for caterpillars in MN.  The photo attached is in my Sons terrarium and the red mushroom looking thing next to it is only a decoration.  We didn’t want to touch the caterpillar for a better picture for fear of a sting, or rash.
How you want your letter signed:  Sincerely, Richard Parkos and Sons

Elm Sawfly Larva

Dear Richard,
Thanks for clarifying the identity of that red decoration with the spots.  As we were formatting the image and color correcting it for posting, we obsessed on its identity.  This is not a caterpillar.  We suspected it to be a Sawfly Larva, but the markings are unusual, but our internet search produced several images that confirm our suspicions that this is the larva of an Elm Sawfly.  We have received images in the past of Elm Sawfly larvae that are yellow, green or pink, and they have a black stripe running the length of the body on the dorsal surface, but those traverse stripes are unusual.  There is a small image on the Wisconsin Department of Natural Resources website with a caption that indicates “Elm sawfly larvae are typically yellow; it is uncommon to find the pink form” but it does not mention the traverse stripes.  Additional images on Insects Galore and Forestry Images also document these unusual markings.  The adult Elm Sawfly is a non-stinging relative of wasps and bees.  Elm Sawfly larvae will not sting and they will not produce a rash.

Subject:  Worm found on oak tree
Geographic location of the bug:  Virginia beach, VA
Date: 08/16/2019
Time: 05:05 PM EDT
Your letter to the bugman:  Found these on my oak tree this morning. 8/16/2019
How you want your letter signed:  Thanks, Duane Heidler

Sawfly Larvae

Dear Duane,
These are Sawfly larvae.  Sawflies are non-stinging relatives of wasps and bees with larvae that are frequently mistaken for caterpillars.  Based on the appearance of the individuals in this BugGuide image, and that the host plant is oak, we suspect your individuals are in the genus

Subject:  Cicada wasp?
Geographic location of the bug:  Hoquiam Washington
Date: 07/21/2019
Time: 10:22 AM EDT
Your letter to the bugman:  This wasp like insect was on my chair. In the forest of Hoquiam Washington. July 19, 2019.
I did not see a stinger, it moved slowly, did not try to fly away. it was approx 1.5 inches long.
How you want your letter signed:  Veronica

Elm Sawfly

Dear Veronica.
This is not a Western Cicada Killer.  It is a non-stinging Elm Sawfly.

Thank you Daniel. We dont have Elm trees here though!

Hi again Veronica,
According to BugGuide:  “hosts include elm (
Ulmus), maple (Acer), birch (Betula), willow (Salix), and basswood (Tilia); adults girdle bark on twigs.”  Additionally, lists of host plants are often incomplete and many species adapt to different host plants due to garden cultivation and species range expansion.

Subject:  Striped Wasp-like bug & a fly/bee type bug
Geographic location of the bug:  Black Mtn Fire Lookout, SW Wyoming, USA
Date: 07/13/2019
Time: 01:23 PM EDT
Your letter to the bugman:  Please identify this wasp and fly-type bug. Hanging out at my Fire lookout.
How you want your letter signed:  Roger Lockwood

Wood Wasp

Dear Roger,
We will take your identification requests one at a time to give each insect its just due.  The wasp is a type of Horntail in the genus
Uroceros, most likely Urocerus flavicornis which is pictured on BugGuide.  We tried to determine the preferred host trees for this Wood Wasp, but we had to zoom out to the subfamily level on BugGuide to learn they feed “on conifers.”  We wanted more details to complete this posting, so we continued to research.  According to the US Forest Service, where the BugGuide provided taxonomic name is actually a subspecies Urocerus gigas flavicornis, they feed on “Fir, larch, spruce, pine, and Douglas-fir.”

Subject:  Is this a bee?
Geographic location of the bug:  CH43 9AJ
Date: 07/13/2019
Time: 03:28 PM EDT
Your letter to the bugman:  What is this? Is it a bee?
How you want your letter signed:  ??

Honeysuckle Sawfly

Dear ??,
We had no idea where CH43 9AJ is located, but a web search produced:  “
CH43 9AJ. Postal code in Birkenhead, England.”  This is a Sawfly, a non-stinging relative of Bees and Wasps.  Based on an image on NatureSpot, we are quite confident it is Zaraea fasciata, and the site states:  “Uncommon with most British records coming from England and Wales.”  According to UK Wildlife, it is commonly called the Honeysuckle Sawfly.

Honeysuckle Sawfly

Subject:  mystery hoverfly
Geographic location of the bug:  Mt St Helens, Washington, USA
Date: 07/11/2019
Time: 08:08 PM EDT
Your letter to the bugman:  Seen June 30, 2019. It’s with body was slightly over an inch (2.5-3 cm) long. Seen at Coldwater Lake, Mt St Helens National Volcanic Monument. A friend thought it might be a species of Tachinid Fly. I would be interested to know if anyone recognizes it.
How you want your letter signed:  Linda Severson

Sawfly: Trichiosoma triangulum

Dear Linda,
This is not a Hover Fly nor any other True Fly.  Flies have a single pair of wings and your insect has two pairs of wings.  The clubbed antennae characterizes it as a Sawfly, a non-stinging relative of stinging Bees and Wasps.  We believe we have identified it as
Trichiosoma triangulum thanks to images on BugGuide.  According to BugGuide:  “Larvae feed on leaves of alders (Alnus), ash (Fraxinus), poplars (Populus), willows (Salix), cherries (Prunus).”