Over the past half-century the Rollins family became known for two things: killing vermin and throwing great parties. Millions upon millions of vermin. And really, really great parties. Within Atlanta society the clan behind the Orkin pest control empire, now worth some $8 billion, became royalty, the envy of Buckhead’s WASP social set. Gary Rollins, the modern-era patriarch, would invite guests by the hundreds to join him and his wife, Ruthie, at the family’s lush 1,800-acre ranch near Cartersville, Ga. His handsome blond son Glen Rollins, the heir presumptive, preferred Gatsby- theme affairs at Boxwood, his English hilltop manor just outside the city, where the 5-acre lawn led to a pear orchard and swimming-pool-size koi pond. So accomplished were those events that Glen’s wife, Danielle, a Dallas debutante, wrote a…