Red dots all over stomach area..Any idea what from

[chessie]

My new dog has red dots all over his stomach area. Was thinking it might be some sort of grass mite, or black fly..My older dog does not have them- mind u he is older and used to the farm so thinking it might just be an allergic reaction. Anyone ever have this happen to their dogs? The marks look like this:

[welder'swife]

black fly. My Plott got those a couple summers in a row when we lived at the old house and she would lay in the grass.