Subject:  Large black flies (Mydas??) showing up in my house.
Geographic location of the bug:  Charlottesville, VA
Date: 03/25/2019
Time: 07:05 PM EDT
Your letter to the bugman:  I’ve noticed several of these bugs around the windows in my house. I will find many of them dead on the ground or sometimes crawling around on the window sill. They are black and quite large (3/4″ long). I’m thinking that they are mydas flies but am not 100%.
Any information you could provide would be greatly appreciated.
If these are Mydas flies where are they coming from and what can I do to get rid of them?
Thank you!
How you want your letter signed:  Zushi

Black Soldier Fly

Dear Zushi,
This is not a Mydas Fly.  Rather, it is a Black Soldier Fly or Window Fly,
Hermetia illucens.  The name Window Fly refers to clear patches in the abdomen, and not because they are found in windows.  Do you have a nearby compost pile?  Larvae of Black Soldier Flies are frequently found in compost piles.  We do not provide extermination advice. 

Black Soldier Fly

Thank you for the reply/information. I will have a look at their abdomen and look for the transparency. I do have a personal compost bin in my backyard garden. I’ve used the compost in soils around my garden and most likely i’ve dug up some of that soil to use in pots that I have some plants in inside my house. This is probably my source.
I understand not giving extermination advice. Once the weather changes for the better I plan on moving most of my plants outside. I will probably go through the process of replacing a lot of the potted soil as well and moving the current soil back into my compost.
Anything else you could provide would be greatly appreciate.
Best regards,
John Boyd


Location: Charlottesville, Virginia

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