Common Flesh Flies
Today I learned that those grey-and-black striped flies, with big red eyes, that scavenge for food are called Flesh Flies
And that it's almost impossible to tell what SPECIES you have, unless you examine their genitalia. I also imagine a genetic test would work, otherwise we wouldn't even know there's a difference between Carnaria and Bercaea and Nodosa.
From https://en.wikipedia.org/wiki/Flesh_fly :
"Generally, only males of this family can reliably be identified to species, and then only by examination of dissected genitalia."
