Just saw a large circle of small fly-like insects in one area of yard. Thought they were maggots, since have seen similar in years past on decomposing food/animals. But this website says they are white; is that just the larvae or might this be something else. They are black with grey/silver wings, only about 1/4 inch in size and don't appear to fly. However, I didn't disturb them so they may be capable of flying.