Probably fungus gnats but who knows without a picture.

I looked up a little info on fungus gnats, but I don't think that's right. These bugs are small and more like the shape of a flea rather than a mosquito. They're much too small and fast to get a photo of, sorry!

The images of fungus gnat on the web are misleading. They are very small, about the size of a flea (or a small gnat). I, too, suspect that this is what you are observing. Tell us more about their behavior if you still think it not to be true.

You can get rid of the fungus gnat larvae by watering with water and insecticidal soap. It won't get rid of the adults but if you water a few times wioth it there won't be any more adults and what's there will soon die off.

A fungus gnat is the size of a fruit fly--a bit smaller than a blackfly. They all look alike except for size.

You often get them with potted plants(especially those bought in department or similar stores) or in unsterilized soil