I think it may be fungus gnats or something. I had little bastards that looked like that before. They kept dying on the buds and what not, that was during my first grow. I was using MG soil, I think that may have been a culprit.
Anyways, I read several ways to fix them, the thing I found that worked for me was getting Bug Off! or some sort of spray from htgsupply.com. I forget exactly what it was but I sprayed the top layer of the soil for a week or so, I also let the soil dry out because I found that they didn't seem to multiply if the soil was more dry. Hopefully this helps. Let me know if you need more clarification.