The above quote from the new Monster Manual (Due out September 30th) described Thri-Kreen as they may appear in most standard D&D worlds. As we all know Dark Sun is far from standard. From the very inception of Dark Sun in the Original Dark Sun boxed set Thri-Kreen were heavily featured and available as a player character race.
This is a companion discussion topic for the original entry at http://athas.org/articles/5e-Thri-Kreen