From the Association site:
The stories detailing an on-campus secret society have origins dating back to the early 1900s. The university’s archives do have proof of two secret societies that exist on campus, but Chapman said there is no society that meets in Cushing, wearing their Rings on their left hand. In fact, since there is no right or wrong way to wear an Aggie Ring, many Aggies choose to wear the Ring on their left hand, making such an indicator of membership impossible.
"The last information we had on them was collected in the 1950s, but I believe they do still exist, probably within the Corps," he said.
A&M's secret societies first appeared in the media in 1913, when the college took action to disband such organizations. The Galveston Daily News published an article about the dismissal of 466 cadets accused of hazing from the college. Before cadets were readmitted, each had to sign a pledge that in part read, "…I will not be a member of any secret student organization; I will not attend any meeting of any class, or club, or of the Corps of Cadets, unless such meeting has been previously authorized by the president of the college."
But the secret societies reappeared again in 1954, when legendary football coach Paul "Bear" Bryant was informed by administrators that four of his top players held membership in a secret organization. The players were among 17 students expelled from the university, making them ineligible for the 1955 football season.
The T.T.s, which stands for either True Texans or Tonkawa Tribe, and the Stickers, an organization believed to have formed in the 1970s, are still believed to be in existence. Chapman, for one, believes that both are alive and well. "Their secret just adds a little flavor to things," he said
http://www.aggienetwork.com/AggieImages/Myths/#5