The Malcorians are a humanoid species on the verge of warp technology in 2367. From Malcor III, they had a unified government ruled by a Chancellor. The Federation was observing them secretly on-planet, but a riot put Commander Riker in the hospital, where his alienness was discovered. This led to a series of incidents (see the TNG episode “First Contact“) that led to the Chancellor of Malcor III deciding that his people weren’t ready for first contact yet. The warp program was postponed so that he could prepare his people with education and social programs for eventual first contact. Scientist Mirasta Yale was given permission to leave the planet with the Enterprise-D.
Malcorian (PDF)