Shares of Rollins Inc. ROL dropped 6.3% toward a six-month low in premarket trading Thursday, after the parent of the Orkin pest-control brand announced a public offering of 38.72 million shares by a selling shareholder. The offering, which was announced late Wednesday, is by LOR Inc., which is a member of the control group that owns more than half of the outstanding shares. The number of shares in the offering represents 7.9% of the shares outstanding as of July 17. The company said Thursday that the offering priced at $35.00 a share, which is 8.1% below Wednesday’s closing price of $38.08. Rollins said it will not receive…