So the ant (allegedly -- I'm eagerly awaiting that source!) saw a dot on the ant in the mirror, and tried to remove the dot on its own forehead. The key point: that looks an awful lot like the identification of the self with the reflected image.

The issue you brought up about the mite is a bit orthogonal to this point. I can give you that the ant was concerned about the possibility of having a mite, and the point still remains that the ant thought it was on its own head only on basis of a reflected image of itself. (Compare to the alternative behavior: the ant tries to get the mite off the reflected image, never making any attempt to remove it from itself.)