Tarsius was a planet which was subjugated by the Federation using the Pacification Programme, at around the same time as Luba, Porphry Major and Helotrix. These three planets were all in Sector 4 so Tarsius may have been located there as well. Industrial production increased by 19% there after annexation, which was assumed to be a result of the Pacification Programme's effects. Also the probable home of the proverbially unsubtle Tarsian warg-strangler.