- This is an article about the Sheliak race. You may also be looking for the star Beta Lyrae also known as Sheliak in the real world.
Unlike most humanoids, the non-humanoid Sheliak preferred to exist in an environment that was the same temperature as their bodies. (TNG: "Starship Mine") The Sheliak were also a xenophobic people, and avoided contact with the Federation whenever possible. This may have been due to the Sheliak attitude that humanoids were an unintelligent and inferior form of life (often pejoratively describing them as "creatures" and the presence of humanoid life as an "infestation").
The Treaty of Armens was established in 2255 between the Sheliak governing body, called "the Corporate", and the Federation which ceded several worlds to the Sheliak. There was virtually no contact with the Sheliak for over a century thereafter, until a human colony on Tau Cygna V was discovered by the Sheliak. In accordance with the treaty, the Enterprise was notified about the human colony, and was given four days to relocate the humans before Sheliak colonization (and human extermination) of the planet began. The Human colonists had adapted to the deadly hyperonic radiation and created a thriving community, though the radiation also rendered transporters inoperable, making a four-day evacuation impossible. The Sheliak showed zero concern for this, and initially refused to grant the Federation any additional time, eventually relenting after Captain Picard found a loophole in the treaty, and used it to force the Sheliak to cooperate. The Sheliak colonists referred to themselves as "the Membership". (TNG: "The Ensigns of Command")