Mydas Fly

Huge Fly!
I just discovered your site because I was trying to identify a giant fly that we discovered yesterday in our fireplace. Nice site! Thankfully, this fly was behind the doors of the fireplace. It was in the around 90F yesterday so he didn’t live long in there and I got a chance to photo him today. I don’t keep the flu open, so I’m trying to figure out how he got in there. I do not see any flies on your site that look like this one. Attached are three photos. Hopefully the ‘perspective’ photo gives you an idea of his size.
by the way, I am in New Jersey.

Hi Chris,
Because of the large size and the clubbed antennae, we believe this to be a Mydas Fly in the Family Mydidae. Adults are predatory, feeding on caterpillars, flies, bees and Hemipterans. Though we are 99% sure this is a Mydas Fly, we are checking with Eric Eaton for a second opinion.

Ed. Note: Here is Eric Eaton’s quick response.
“That certainly is a mydas fly! Is the image in black and white? If so, it could be Mydas tibialis, which has no red band like M. clavatus, but has orange legs on a dark brown/black body. Mydas flies seem to be attracted to large, standing, hollow trees, so it might have mistaken the chimney for a tree and flown in. Flues do not close tightly enough to exclude insects is my bet, and so the thing made it all the way to the fireplace. They sure are intimidating, the loud droning buzz alone being quite ominous! Luckily they are harmless to people. Eric ”

2 thoughts on “Mydas Fly”

  1. We have a very large fly that is burrowing underneath our raised patio. It appears to be all black in color. Do mydas flies burrow or could it be something else? Could they cause damage? We are in upstate ny.


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