The Irapina are a people from the Sagittarius Arm of the galaxy. They were headed toward the United Federation of Planets, dominating all species in their path. Their arrival was estimated at one thousand years, give or take a hundred. They are like the Arivne but emotional and belligerent.

They look like a cross between an insect and a centaur. They have four legs with three joints covered in shiny black chitin. Their bodies were shiny brown with bits of green and blue. The thorax had black bristles, two arms, and a head. The arms were mechanical looking, ending in tentacles with one arm bigger than the other. Each of the four elbows had a hooked claw. The head was triangular with bubbly red eyes. They had a black tongue that went in and out, and finished off their bodies with a scorpion-like tail.

The life span of some Irapina is as long as two thousand years. This group harvests organs from other Irapina for use as replacement parts.

Their invasion force consists of ten billion of the ruling class. They have four planet sized ships approximately twenty-five thousand light years away. They were moving quite slow.

At last report, Spock and James Kirk frightened them into changing course. Their new heading is for the Romulan Star Empire. (TOS novel: Planet of Judgment)