The Irapina were 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, as they were telepathic, but were also emotional and belligerent.
They were about the size of a horse and look like a cross between an insect and a centaur. They had four legs with three joints covered in shiny black chitin. Their egg-shaped bodies were shiny brown with bits of green and blue. The thorax, rising from the front, 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 that looked like two clusters of salmon eggs and a small hole for a mouth. The mouth had a slender black tongue that went in and out, and finished off their bodies with a thick barbed scorpion-like tail.
The life span of some Irapina was as long as two thousand years. This group harvested organs from other Irapina for use as replacement parts.
Their invasion force consisted of ten billion of the ruling class. They had 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 was for the Romulan Star Empire. (TOS novel: Planet of Judgment)