Mydas Fly

Large Wasp in AZ
Location: Tuwhicson, AZ
June 24, 2011 8:52 pm
I took this picture of this huge wasp-type insect in Tucson, AZ and I’ve been trying to figure out what it is. It was maybe about 1.5” – 2” in length. The closest-resembling thing I’ve been able to find is the tarantula hawk, but I’ve only read about those having black abdomens/bodies with orange wings. Can you please identify my bug?? Thanks!!
Signature: Brooke

Mydas Fly

Hi Brooke,
This is not a Wasp.  At first we thought it might be a Robber Fly, and we found a Robber Fly from Arizona on BugGuide,
Archilestris magnificus, that is colored similarly, but alas, the antennae are quite different.  We then shifted to what our first impression was, that this might be a Mydas Fly, and we found a photo from Colorado on BugGuide of Phyllomydas phyllocerus  which matches quite nicely.  Additionally, there is a nice closeup of a related individual from Florida on BugGuide that also looks close.  We cannot say for certain that either the genus or species is correct, but we are relatively certain that this is in fact a Mydas Fly.

Hi Daniel,
Thanks for your help and your quick response!!!  Your website is excellent.  I started thinking after I posted my photo that it might be a fly because of the trumpet-shaped thing coming out of its face/mouth – or whatever flies bite/suck with.  I’m not up on my insect terminology.  That is one huge fly!  I’m relieved to know that it’s not a tarantula hawk.
Thanks again,

Hi Brooke,
You are correct that wasps and flies have very different mouth anatomies.  Flies have a proboscis designed for sucking up food, and wasps have mandibles for chewing food.  Here is how the Utah Education Network website describes the mouth of a fly:  “Flies cannot chew. They have to suck up their food. Flies have mouth parts that absorb food like a sponge. Their food has to be in a liquid form in order for them to eat it. They have a tongue shaped like a drinking straw to slurp up their meals. Flies that eat nectar or blood do so by using their tongue which is called a proboscis. Even flies that eat other insects do so by sucking out the insides of their victims.”

Eric Eaton confirms ID
Sure looks like a Mydas sp. to me.  Nice detective work!

7 thoughts on “Mydas Fly”

  1. Mydas Fly in Gila Bend, AZ
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  2. Hello everyone.Ok i live in south Georgia and while sitting in the back yard i spotted this red bodied with black wings that did more crawling around but did fly away.It was not aggressive.I’m trying to figure out what it is.I never seen this bug before.The closest i found out was it being a Mydas fly but does not look exactly like the mydas fly.anybody got any more imfo to share.Thanks………………………..Brian J

  3. We just found a large one in our backyard today (7/20/2019) in metro Phoenix, Arizona. It looked just like the picture above, black upper-body and wings with a full orange-lower body. It was huge, about 2 inches. We captured it in a jar and inspected it before letting it go. It certainly looked like a giant fly with the shape of the eyes, long mouth parts, legs and antenna.
    I’ve lived in Arizona my whole life and never seen one before. Are they native to Arizona?

    • We cannot currently access BugGuide to verify the range of Archilestris magnificus, but this FlickR image from Arizona leads us to believe it is a local species for you.

  4. Hi I saw something like it but top and was orange and bottom was was purple front was black head it was very pretty non aggressive it that the same thing or something else

  5. I have these bugs in my backyard and there’s lots of them flying around my lawn and I said hundred of them and they look like mydas fly but they are tiny with orange but and black body. Can someone tell me if they have this kind of bug in their backyard? I noticed them a couple months ago, they are the size of a regular fly but cuter they are fast.


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