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Entomology (Study of Bugs)/Stung by a Parasitic wasp larvae I believe


Parasitic Wasp larvae
Parasitic Wasp larvae  

Photo 2
Photo 2  
I was working in my garden 4/1/2014, actually collecting grubs for my Bluebirds and digging. I picked up a grub and what I thought was a young grub without the developed face and placed them both in my left hand (no gloves) and continued digging. Suddenly I experienced a deep pain that ran up my arm and I could tell it started at my finger.  I obviously threw down the worms, regained my composure from the pain and picked up odd worm with shovel in order to photograph it while calling my husband as well. I wasn't sure if I'd have an adverse reaction and wanted him to be aware of what happened. My finger swelled and continues to feel the pain however I believe it is getting better after 4 days. It hurts to run water over it when washing my hands but I think this is due to the droplets stimulating the area I was stung in. The area turned white when it happened, swelled as I mentioned on my left index finger.  Should I be concerned?  I didn't visit the doctor but instead did lots of research online but finding a photo of this worm has proven difficult. Even harder is learning whether I should be concerned about the sting as I couldn't find that info either. Here is the photo and by the way, the pointed end moved forward so I assume that is the head. If you believe the larvae isn't capable of stinging me that I must assume it was a spider but the timing was specific to me handling the worm.


Thank you for including the images with your question.

What you have there is a fly larva, either of a mydas fly (family Mydidae) or a robber fly (family Asilidae).  In both cases, larvae are predatory, especially on scarab beetle grubs.  So, finding this one in the company of grubs is no surprise.

The larvae do have enzymes, and perhaps some kind of venom, that they inject into victims to paralyze them and begin the digestive process.  That can't feel good to someone they bite in self-defense!

I would love to have you e-mail me these images, as I could use them in a blog post.  Larvae of these kinds of flies are very seldom seen, but your pictures are detailed enough to leave no doubt as to what they are.  Further, I could then post the images to places where an expert on robber flies and mydas flies could tell me (and you) which this is.  

Please e-mail me at:

Thanks, get well soon!


Entomology (Study of Bugs)

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Eric R. Eaton


I answer insect and spider identification questions ONLY. Attach images if possible. No "what bit me?", "what do I feed this bug in captivity?", or science fair project questions please. NO TECHNICAL QUESTIONS ABOUT INSECT PHYSIOLOGY.


Principal author, Kaufman Field Guide to Insects of North America. Professional entomologist employed previously at University of Massachusetts, Chase Studio, Inc., and Cincinnati Zoo; contract work for West Virginia Department of Natural Resources, Smithsonian Institution, and Portland (Oregon) State University.

Author, Kaufman Field Guide to Insects of North America, Missouri Conservationist magazine, Ranger Rick, Birds & Blooms, Timeline (journal of the Ohio Historical Society). I have contributed to several books as well.

Oregon State University, undergraduate major in entomology, did not receive degree.

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One of the top 50 experts in all categories for, 2009.

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Principal author of the Kaufman Field Guide to Insects of North America, Smithsonian Institution (contract), Cincinnati Zoo (employer), Portland State University (contract), Chase Studio, Inc (employer), Arkansas Museum of Discovery (guest speaker). Currently seeking speaking engagements, leadership roles at nature festivals, workshops, and ecotours.

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