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Entomology (Study of Bugs)/Mydas fly or some type of bee?


Flying Close to ground
Flying Close to ground  
Sitting on leaf
Sitting on leaf  
QUESTION: Hello. my name is Lisa. I live in Central Connecticut; garden zone 5b.  I am an avid gardener and I do so 100% organically. I've been in my home for 25 years and have had a 100% organic garden every one of those past 25 years.  My garden thrives on seaweed fertilizer, homemade comfrey tea (from my huge comfrey patch), comfrey leaves, organic compost and vermicompost from my red worm beds.

I tried something new this year. To control weeds and help lock in moisture I put a 6-8" deep layer of hard-wood chips over my entire garden. The wood is a combination of maple, birch and cedar (got it for free from a local tree guy).  The wood chips really increased the population of beneficial insects and my plants are thriving.  All my heirloom tomato plants (23 different varieties this year) are bushes.  Each being 6+ feet tall and several feet wide. I've always had an abundance of honey and bumble bees but this year I have lots of lacewings, ladybugs and even praying mantis.  They all seem to really enjoy the bronze fennel and coriander Of course there are also the usual spiders, garter snakes, crickets, etc., I welcome them all.. I grew up catching snakes, frogs and bugs with my 2 older brothers and nothing outdoors scares me.

Over the past few weeks our temps have been incredibly hot. Temperatures over 100 and high humidity and dew point levels has resulted in mantras h having a heat index Vallejo to 115 degrees. With the onset of the heat came something new to the garden.... a whole lot of them.  A new type of bee looking flying insect. There were a few early in the season but when the real heat kicked in, the number of these flying insects increased a substantially. The number flying in close proximity to one another ranges from about 50 to well over 100 on any given day. The heat definitely makes them more active.

There are 100 or more swarming during the hottest hours in an area about 30 x 50 feet. In some spots they land in clumps on top of each other.  They are not aggressive and so far, they have not stung.  I walk right through large amounts of them and they don't seem to mind.   They seem to fly close to the ground most often, however, they also surround one particular tomato plant (german green variety) and also hover over the privet hedges that separate my garden from the road.  They are not landing on flowers or collecting pollen.

I did some web research and the closest match I found is the Mydas fly. Perhaps these are a variety of Mydas fly, but those I have are more colorful than any photo I found online and from what I read, these "flies" don't tend to swarm or stay in groups.  

My garden edge is against the road and people walking down the sidewalk are often scared by the large number of these bee-looking critters. If I can confirm that they are in fact harmless Mydas flies then I'll put up a sign to put passersbys at ease.  The feature that doesnt match what I have read is that what I have has a orange abdomen from thorax to tail as well as a half-yellow band and I haven't found any online photos of Mydas fly matching the color pattern and again, it appears to be a true swarm that is active daily and I could not find any information on Mydas fly swarms. Can you please help me identify these flying insects?

I am having a great deal of difficulty attaching a photo , for some reason it will not allow me to browse to the folder the photos are in, so instead I'm providing a link to a folder containing the photos:

If the first didn't work, try this.

I have two videos that you can see here:

Or, separated,


The video showing the insects flying is showing about 5% of the population.

If for some reason the video links do not work, please give me an email address in your reply and I can send a link directly to your email address.

I'm very curious to learn if I've made the correct ID and if not, learn what the critters really are (and if they are in fact harmless?).

Thank you.
Lisa L

 This is one of the Ground wasps or Diggar wasops This particular one is known as the Blue winged wasp  , Scolia dubia. It is a transient from Japan and is great for your garden. They especialll like Japanese beetles.  The females can sting but are basically harmless

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QUESTION: Thank you for your fast reply and very accurate information. I looked up the "Scolia Dubia" species and you nailed it!  (A good thing).  I'm neither afraid of bees, nor allrgic to their sting, but I must admit that working with my head in a cloud of 100 or more of these is a bit intimidating.  If a female does happen to sting me, does it release a pheromone like yellow jackets produce that will send all of them after me?, or will it just be that one sting? If I do get stung, will it result in the sting area becoming paralyzed as the grubs do?  

About a month ago I unknowingly dug into an underground yellow jacket nest and by the time one of them stung me, they were ALL heading toward me resulting in 16 stings.  I consider myself lucky because if i hadn't made it to the inside of my house, it would ha e been a lot worse.  They were in my clothes and still stinging as I was getting the clothes off me! Not fun.....  I don't need another encounter like that 🐝💉

There is no way for me to avoid working in the blue wasp area as they cover the majority of my main garden which is at peak season.  Is there anything I can do to reduce the risk of getting stung?  

It's good to know I have another beneficial insect in my garden and am thrilled that they target the grubs!  I only wish they also ate the vine borer larvae because they wreaked havoc on my squash and zucchini this year. I surgically removed as many borders as I could locate, but they stayed one step ahead of me......

Guess I need to train my blue wasps to eat borer larvae!

Again, thank you for the fast reply and accurate info.

I would appreciate any advice about working within these wasps without getting stung.

Lisa LaBonte

ANSWER: I cannot predict the behavior of these wasps toward you but if they have not stung you by now I think there is nothing to worry about. You cannot the behavior of Yellow jackets with that of digger wasps. Scolia are not social wasps so they do not have a common nest to protect. The females are solitary wasps. A sting by a Scolia would not erupt all of the others against you

walter hintz
Biology department
Lakeland community college

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New fly
New fly  

New fly
New fly  
QUESTION: Thanks again. The information is helpful. I'm amazed with the sheer number of them I have especially since they live solitary. It certainly explains the dozens of holes that suddenly appeared in my garden .

On another question I found another critter today that I've not seen before and I'm attaching pictures . It may look dead, but it's not. I put it in a jar in the refrigerator for several minutes to bring it to inactivity long enough to take a couple photos, it actually started flying again as I was taking the last one, LOL. Is this just some type of horsefly or something else?

Hi Lisa
This is a bee fly. It is Xenox tigrinis the Tiger Bee Fly. Insects that will feed on flies but not bees will avoid this bee fly. In addition to being a good pollenator some bee flies will enter a bees nest and lay an egg. When the maggot hatches it feeds on the stored pollen and then eats the bee maggot

Entomology (Study of Bugs)

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Walter Hintz


I can answer any questions about insects and spiders.


I have taught science for over 57 years. I am presently teaching biology at the college level. I have done extensive graduate work in entomology.

Momentum Magazine The Ohio Journal of Science

B.S. In Ed Kent State Unuv M.Sc The Ohio State Univ National Science Foundation Fellowships: Electron Microscopy Univ of California Entomology Kent State Univ

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