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

Subject:  wasp
Geographic location of the bug:  Wheatland, Wyoming
Date: 08/07/2018
Time: 02:39 PM EDT
Your letter to the bugman:  What’s this bug?
How you want your letter signed:  Roger Lockwood

Male Horntail

Dear Roger,
This is a male Horntail in the genus
Urocerus, which we identified thanks to this BugGuide image, and there is a comment attributed to Dave Smith on that posting that states:  “Urocerus sp., male. Could be either U. albicornis or U. flavicornis. The males are difficult to separate.”  Horntails are sometimes called Wood Wasps, but they do not sting, and no male wasps are capable of stinging anyways.  Here is an image from our archives of the female Urocerus albicornis and here is an image of the female Urocerus flavicornis.  The ovipositor of the female is used to lay eggs beneath the bark of conifer trees and its appearance is responsible for the common name Horntail.

Subject:  a flying insect , black with red on bottom
Geographic location of the bug:  Luzerne county, PA
Date: 08/05/2018
Time: 05:02 PM EDT
Your letter to the bugman:  I never saw this insect before.  It resembles a wasp and looks like it has a stinger on it’s end, the abdomen is a bright red , has wings and the rest of it black.
How you want your letter signed:  Dan

Black and Red Horntail

Dear Dan,
The only other image we have on our site of a Black and Red Horntail,
Urocerus cressoni, looks amazingly like your image.  According to BugGuide:  “hosts include Fir, Spruce, and Pine (Abies, Picea, Pinus).”

Thank you. Definitely looks like the picture you sent.


Subject:  Identification assistance sought
Geographic location of the bug:  My Ashland, OR ~6000 ft above sea level
Date: 06/27/2018
Time: 03:06 AM EDT
Your letter to the bugman:  I am guessing it’s a mitis fly but I couldn’t find one that looks exactly like it
How you want your letter signed:  Susan

Elm Sawfly

Dear Susan,
This is an Elm Sawfly, a non-stinging relative of Wasps and Bees.

Subject:  What is this
Geographic location of the bug:  Handworth middlesex
Date: 06/27/2018
Time: 07:52 PM EDT
Your letter to the bugman:  Can you identify this it was on my rose not seen one before
How you want your letter signed:  Wayne

Large Rose Sawfly

Dear Wayne,
This is a Large Rose Sawfly,
Arge pagana.  Sawflies are non-stinging relatives of Bees and Wasps that have larvae that are frequently confused for caterpillars.  According to Garden Safari:  “The Large Rose Sawfly is a quite beautiful and shiny animal. The animal is entirely black, except for the abdomen which is yellowish orange. Because of the dark, blackish wings, which are kept over the abdomen, the orange colour may not always be clearly visible. The legs are usually entirely black as well. The animals are not capable flyers, slowly flying about with the legs hanging down. In flight they are quite similar to to some flies, such as the St Mark’s Flies, appearing in spring as well. Males can be told apart from the females by looking at the antennae. Males have wire-like antennes, which are the same size just about everywhere. Females have antennae which get slighter thicker going upwards. The Large Rose Sawfly is on the wing in spring and early summer mainly. Depending on the temperatures most are seen from March to June. Like all Sawflies female Large Rose Sawflies are in possession of a little saw. With it they make rectangular cuts in the fresh shoots of the host plant. In the cut a bunch of eggs is being deposited. The larvae hatch quite quickly and move in a group to the freshly emerged leaves. Young larvae stay together for quite some time, capable of eating the entire shoot. Older larvae lead a more single life and eat from older leaves as well. The larvae are very similar to caterpillars and green with black dots and points. When they feel threatened they assume the so-called S-position. This can be seen in many other sawfly larvae as well. To pupate a firm whitish cocoon is spun near or in the soil. The cocoon actually has two covers. The inner one is smooth and firm. The outer cover has the design of a net. It is the pupa overwintering. The larvae are found on wild and cultivated roses. ”  According to iNaturalist:  “The larvae are gregarious and live in colonies feeding on rose leaves.”

Very interesting! How much damage can they do and all so I found a mint Beatle that was nice to look at and thank you for your answer kind regards Wayne

Hi again Wayne,
We have no personal experience with the Large Rose Sawfly, but from what we have read, the damage is done by the female laying eggs and by the larvae eating leaves.  A large infestation might defoliate a rose bush, but leaves will grow back.  A healthy rose bush should have no problem surviving a small infestation.

Subject:  Enormous hover fly?
Geographic location of the bug:  Isabella, MN
Date: 05/25/2018
Time: 11:26 AM EDT
Your letter to the bugman:  Hi!
We saw this guy on our cabin screen in Isabella, MN (far northwestern corner of the state) on May 24th. He’s about an inch long from head to tail! We’re curious about what he is. Thanks!
How you want your letter signed:  Krista

Elm Sawfly

Dear Krista,
This is not a
Hover Fly.  It is an Elm Sawfly.  Unlike Hover Flies which are True Flies with a single pair of wings, Sawflies are non-stinging relatives of Wasps and Bees that have two pairs of wings.

Awesome! Thank you so much! I figured it was much too big to be a hover fly!

Subject:  What’s this?
Geographic location of the bug:  Slovakia, central Europe, mixed oak-pine woods
Date: 05/19/2018
Time: 11:05 AM EDT
Your letter to the bugman:  I found this bee while hiking through the woods picking up mushrooms (I assume it’s a kind of a carpenter bee, something from Xylocopinae) but I can’t seem to find one that looks like it on the internet. It’s May currently, pretty warm outside already (20°C), but I’m not sure how long has the specimen been lying on the ground (I found it dead already). Also, I should mention, it has tentacles with orange endings wider than the rest of the tentacle.  There’s no section that would visibly divide between the abdomen and chest area. Also, the bee has really long hind legs with slight yellowish colouring at the end of them. It’s almost 3cm long. Has see-through wings about the same length as the bee itself. Has visible mandibulae and maxilae.
How you want your letter signed:  T.


Dear T,
This is not a Bee.  It is a Sawfly, a non-stinging relative of Bees and Wasps.  It might be a Birch Sawfly,
Cimbex femoratus, which is pictured on iNaturalist.