Currently viewing the category: "Square Headed Wasps"
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Subject:  Mason Was planning – I think!
Geographic location of the bug:  SE Louisiana
Date: 07/29/2018
Time: 09:47 AM EDT
Your letter to the bugman:  Found two of these tiny wasp-looking creatures leaving their baby creatures in tiny perfectly round holes in my shed wall. Got a photo of one but the other flew off before I could get her. I say ‘her’ because she was a bit thicker in the abdomen and I thought that maybe she was carrying eggs. After an Internet search I figured that they are probably Mason Wasps, but I’m wondering if you can tell me more. I’m an avid outdoors person and am astounded that I’ve never seen these before! I’m quite familiar with Carpenter Bees, they like my shed as well. An ID would be appreciated!
Thanks,
How you want your letter signed:  Margie from Louisiana

Keyhole Wasp Nesting

Dear Margie,
We feel pretty confident that this is NOT a Mason Wasp in the subfamily Eumeninae, as those tend to be bulkier, based on images posted to BugGuide.  We believe this is a Thread-Waisted Wasp in the family Sphecidae, but we would gladly accept any identification assistance our readership can provide.

Keyhole Wasp Nest

Thanks, Daniel! I also posted to the Insect ID page on Facebook. One of the readers there thinks that it is a Crabronid Trypoxglon? He said “Not a potter, mason, mud dauber, or thread waisted.”
What do you think about this ID?
Margie
Hi Margie,
The large head was one of the features we observed, and according to a comment by Eric Eaton on BugGuide:  “All other our species (the ‘keyhole wasps’) nest in pre-existing tunnels like beetle borings, sealing the finished nest with mud. Paralyzed spiders are used as provisions in each cell.”  That seems like a very good identification to us and we like the name Keyhole Wasp.
Hi,
I’m looking at your site and searching under the Trypoxylon group I found this guy – I think it is the same:
Is this one called a keyhole wasp, too?
Margie
Hi again Margie,
That link was from BugGuide, not our site.  The name Keyhole Wasp was used in a comment by Eric Eaton.  When we researched the common name Keyhole Wasp, we found it in reference to the Mason Wasp
Pachodynerus nasidens on BugGuide.
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Subject:  bee or wasp
Geographic location of the bug:  Baltimore Ontario
Date: 09/18/2017
Time: 10:11 PM EDT
I found this little guy walking back and forth on a milkweed plant. I did not realize (until I reviewed my photos) that one of his wings is damaged. I feel sorry for the little guy. I don’t know if this is a bee or wasp. I am leaning towards a bee. Hope you can tell me would be great to know. Thanks
p.s. may have sent this twice computer issues.
How you want your letter signed —
terri martin

Square-Headed Wasp

Dear Terri,
The head-on view you provided made it easy for us to identify your Square-Headed Wasp in the subfamily Crabroninae, and though it is not the same species, it looks very similar to this BugGuide image.  Because of the striping pattern on the abdomen, and the yellow legs and antennae, we suspect your individual is in the genus
Crabro like this BugGuide image.

Square-Headed Wasp

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Subject: Predation
Location: Sussex County, NJ
July 31, 2017 8:44 am
I witnessed a square-headed wasp (Family Cabronidae, I believe) take down a large syrphid fly this morning and thought I’d share the photos. Also, wondering if you might be able to narrow down my ID on the wasp for me?
The attack was remarkably fast with the wasp landing on the fly and quickly subduing it. Eventually the wasp dropped the fly as it seemed that it was too large for the wasp to carry more than a very short distance. Interestingly, an hour later, the body of the syrphidae was gone – so did it recover or did something else come along and dispose of it? Fascinating.
Signature: Deborah Bifulco

Square-Headed Wasp and Drone Fly Prey

Dear Deborah,
Thanks for sending in your amazing images that are greatly enhanced by your written observations.  Speculate is the best we can do for the subsequent exploits of the Drone Fly, but we can be certain that it was alive after the encounter.  We would like to speculate that after that spectacular attack, the Square-Headed Wasp partially glided, and partially dragged her prey to her nest to serve as fresh meat for her developing brood.  Of the Square Headed Wasps in the subfamily Crabroninae, BugGuide states:  “Some nest in hollow stems or in abandoned galleries in wood, others burrow in the ground. Prey is mostly flies, but some utilize other insects.”  Exactly a year and two days ago, you submitted a very similar Food Chain image. that appears to be of the same species, both predator and prey, and at that time, we identified the genus as possibly
Ectemnius.  We will look into this more thoroughly.

Square-Headed Wasp and Drone Fly Prey

Hi Daniel,
Thanks so much for your very informative response!  And forgive my senior moment in forgetting the photo I sent to you last year.
I actually wondered if the wasp had just paralyzed the Drone Fly, or if it was dead.  But it certainly makes sense that it would be alive, especially as it would be a food source for the wasp-kids.  I have a small colony of Great Golden Diggers and frequently see them carrying very large katydids into their nests.
I have found with insects that the more I learn, the more I want to know.  J
Best,
Deborah

You are most welcome Deborah.  We can always depend upon you to send in great images.

Square-Headed Wasp and Drone Fly Prey

Square-Headed Wasp and Drone Fly Prey

What's That Bug? does not endorse extermination

Subject: Predation
Location: Andover, NJ
July 28, 2016 8:16 am
I was lurking around my butterfly garden this morning and happened to see this small wasp (Eumenine maybe?) subduing a large syrphid. Amazingly, the wasp took off with her prize with seemingly little effort!
Signature: Deborah Bifulco

Square Headed Wasp preys upon Hover Fly

Square Headed Wasp preys upon Hover Fly

Good Mornind Deborah,
What an amazing image.  This is a Square Headed Wasp in the subfamily Crabroninae, and we believe that based on this image from BugGuide, that it is in the genus
Ectemnius.  According to BugGuide:  “most nest in decayed wood (logs, stumps), sometimes in sound wood; provision the nests with Diptera.”   The prey appears to be a Drone Fly.

Thanks so much, Daniel!  I was a bit off on my wasp ID, wasn’t I?  Even with multiple field guides, I still find it rather challenging to get the subfamily correct.  But it sure is fun trying!  I just wish our summers lasted longer – once winter comes, I’m lucky to find a shield bug.
Debbi

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Subject: Mystery wasp
Location: raymond james stadium FL
October 16, 2015 5:43 pm
based on some peoples opinions, I believe this might be Trypoxylon, but I wanted to here your opinion on it as well.
Thank you!
Signature: Cicada Lover

Square Headed Wasp

Square Headed Wasp

Dear Cicada Lover,
We believe that this is a Square Headed Wasp in the subfamily Crabroninae which is well represented on BugGuide.  Though the subfamily contains the genus
Trypoxylon, we cannot state with any certainty that is the correct classification.  Perhaps one of our readers will supply additional information.

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Subject: Unknown Pollinator for Orange Coneflower
Location: North Carolina, United States (near Chapel Hill)
September 14, 2014 8:36 am
Hello, I have recently been studying bugs and have been unable to identify the little bugger you see below. The bug itself seems to hang around the orange coneflower (rudbeckia fulgida) quite a bit and always lands on the outer extensions of the head of the flower before heading to the center portion. Thanks!
Signature: Connor McFadden

Possibly Square Headed Wasp

Possibly Square Headed Wasp

Dear Connor,
Your image is not sharp enough to be certain, but we believe this might be a Square Headed Wasp in the subfamily Crabroninae, and it looks similar to this image posted to bugGuide.

What's That Bug? does not endorse extermination