Hi, when I was placing my mason bees in the hatch tray above my nest I saw a little tiny fly thing crawling into a crack from where I set the cocoons. And then I noticed a little hole in one of the cocoons! so I placed the infected cocoon? in the plastic storage container (I stored the cocoons in all winter) to let it hatch (if it hatches) away from the other cocoons, and the next day I saw that the storage container was getting too much sun so I moved it to a more shadier location, and beneath the storage container I saw about a dozen of the little tiny flies!

I think I already know the answer to this, but are these flies harmfull?

Thank you.

Ethan.