Madonnastripped down and beat the heat by going topless in a series of artsy Instagram pictures, RadarOnline.com can reveal. The Ray of Light singer, 65, captioned the sultry snapshots with the words: “Hot Fun in The Summer Time………” The first photograph revealed the Queen of Pop fully clothed, but as the series progressed, the images became racier. One some, she wore strategically placed jewelry followed by pictures that carefully cropped or covered her chest. The last picture showed her being embraced by an equally topless mystery man, who has previously been featured in her social media post…