To dream that you see an x as being the marks on the spot, then such dream suggests to look deeper into some things that you werent able to see.
Dream dictionary: x marks on the spot dream meanings
If you put the big sign of x on some kind of map, it means that you already have a target and know exactly what to do if you wish to succeed. The small x that is almost impossible to see shows that you have a target, but have no power or will to go and get it. Perhaps at this time of your life you are not prepared all of your steps, that is why the x is written in such a small letter.
In the dream you are x-rayed, this dream marks betrayal. This may be your partner or a situation. You must examine the situation from the very deep if you want to find out the answer. Also this can show that you are looking for the solution of the problem that is why you examine everything very carefully.
…Flies in dreams signify impending illness, generally of a mental nature, and misfortunes of various kinds. For example, a man whom I met abroad told me that he continually dreamed he was tormented with flies, prior to an attack of temporary insanity.Again, shortly before her children were attacked with scarlet fever, a lady dreamed her room was inundated with green flies; whilst someone else informed me that before losing her billet in an office she dreamed she was bitten on the lip by a blue-bottle, and the pain was so real that, on awakening, she examined the spot to see if there were marks to show that she really had been bitten….