Entomology (Study of Bugs)/fly ID help


Spilomyia longicornis?
Spilomyia longicornis?  
Hi Eric,

I may not have made it to the IECC conference this year, but I've had a busy summer of observing many insects in MT. Yesterday I saw and got a photo of this amazing yellow jacket fly mimic. I've tried to ID it and have come up with Spilomyia longicornis. But the information I found indicates MN as the closest part of its range. Do you think my guess is correct? And if so, is this a rare sighting for MT?

Thanks for any help you can provide.

Best regards,


Hi, Glenn:

Well, there are apparently eleven species, 4 of which are widespread in the western U.S., so it might be one of those.  Most species look very much like this, so you might have to put the specimen under a microscope to get a species ID.  Meanwhile, this link is to a fairly recent key:


I clicked on it and got an "untrusted connection," but doing a Google search might have gotten an alternative site.

Anyway, I can certainly confirm the genus ID as correct :-)  Keep up the great work!


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.

Awards and Honors
One of the top 50 experts in all categories for AllExperts.com, 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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