Waved Light Fly

Subject: Stumped on fly (?) ID
Location: Galesburg, IL. USA
May 27, 2013 11:55 pm
Haven’t seen one of these in this area, Galesburg, IL, before. Was sleeping with wings open under outdoor lights along with the usual moths, and etceteras. Shot around midnight, Memorial Day. The wing span is close to 1.25” across. Thanks for any assistance.
Signature: Susurra Fonseca

Waved Light Fly
Waved Light Fly

Hi Susurra,
It took us a bit of searching, but we eventually identified your Waved Light Fly, Pyrgota undata, thanks to images posted to BugGuide.  This is a new species and we do not have a classification for it except “Flies” as a broad order category.  None the subcategories that we could possibly classify it into have common names.  According to BugGuide, it is in the family Pyrgotidae, superfamily Tephritoidea, no taxon “Acalyptratae” and then the order Diptera, the Flies.  So, though the species has a common name, no subcategories have common names.  BugGuide does state this about the life cycle:  “Life history: Female lights on a feeding May beetle, causing it to take flight. Pyrgotid then oviposits into beetle’s back while soft parts are exposed in flight. Flies usually attack female beetles only and may pursue them under lights. Larvae is about 1 cm long, takes about 14 days to kill host beetle and then consumes entire interior. Fly pupates inside host remains and pupates there, emerges following spring.”  Thank you for this interesting submission and for providing a photo of an underrepresented species for our site.  

Thank-you. I’ve photographed a lot of insects, especially insects that geographically
don’t belong in this area, i.e. blue cycad butterflies. Never saw that particular fly before.
The closest ID was in the bee fly family, no exact match & this had no tufts of hair on it’s body.
I’ll forward some other photos of the same fly after I ‘clean them up’ just a bit for clarity, so you
can have some other images for the site.

We will be away for ten days, so we hope your photos don’t get lost in the backlog we expect upon our return.

Perfect time for me to procrastinate. Also, I remember the night I first saw the wave light fly,
there were a lot of ‘June’ bugs then. Maybe that’s what led it to here. Just maybe.

1 thought on “Waved Light Fly”

  1. One of these landed on my windshield just last week while waiting at the bus stop in northern VA. I thought it was some freak sort of wasp and promptly put all the windows up to keep it out of the car. Apparently, my fear was unnecessary. Thanks for quelling my panic!


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