FORMICS aka BUGGERS

Homeworld: Bugger Homeworld (destroyed in 2070)

The Formics, more commonly known as Buggers, is an insectoid interstellar communal civilisation socially structured much like Earth’s ants. Biologically, they started with an exoskeleton, but through time and evolution, they had evolved an internal skeleton, and shed their external one. Drones retained vestigial antennae and the queen retained vestigial wings. The Formics share a single hive-mind. If the queen dies, all the Formics lose all will and intelligence and die shortly afterwards. Throguh this hive minde, the Formics are naturally able to communicate instantaneously, regardless of the distance; They live in vast underground colonies in complete darkness.

Humankind first learned of the buggers during the 3rd millennium with their so-called 1st invasion of the solar system. The buggers had set up an advance post on Eros, which they protected using their advanced gravity manipulation technologies. The 2nd invasion arrived 20 years later, with the apparent intention of colonizing Earth. The war lasted 10 years. Because Formics are hive minded, they assumed intelligent life must naturally be hive minded, thus when they killed humans they "gave it no more thought than a human would clipping his toenails". Once they realized that humans were sentient individuals, they immediately halted their attacks. Unfortunately, humanity did not realize this fact and while rhere never was a 3rd invasion, Earth moved on the Formic homeworld and destroyed it, killing the queen and therefore breaking the hive-mind. The race was later restarted by the implantation of a surviving queen cocoon on another world.

Source: Ender’s Game (Orson Scott Card)