The Seltorians are an extra-galactic race of insectoids from the M81 galaxy in the Star Fleet Battles universe.
Seltorians were genetically-engineered by the Tholians to be their servitor race in the M81 galaxy. They served as their army of enforcers who suppressed piracy and uprising, and were equipped with warp-capable warships that were armed with the Shield Cracker (which took down enemy defensive energy shields).
Eventually the Seltorians revolted against the Tholians and exterminated most of them, chasing the remainder out of the M81 galaxy. The secret to their success was modifying the Shield Cracker into the Web Breaker (which not only disabled the Tholian Web but collapsed the hollowed Tholian worlds).
Seltorians now dominate the M81 galaxy. Still seeking vengeance against the Tholians, Seltorian fleets have been sent out to other galaxies in search of Tholian remnants and in pursuit of the remaining Tholian forces, one of which is in the Milky Way galaxy.
The Seltorians are a 6 ft tall bipedal insectoid species. Queens if provided with sufficient food are capable of laying millions of eggs, rapidly producing new armies. Seltorians have a lifespan of 5 years and mature in 6 months. The great majority of the Seltorians are female and workers. Few males are born, and they are Rams who if they mate with a queen they die.
Among the Seltorians, most are workers. One in 10,000 female workers undergo a metamorphosis into a nearly-immortal "expert" who becomes a technician. Males that never mate likewise undergo a metamorphosis into a "Sage", nearly-immortal officers who run the Seltorian military and society.