The Menthars were an ancient warp capable species that were the cause of their own extinction during their long war with the Promellians, that ended with the battle at Orelious IX during the 14th century. The homeworld of the Menthars was located in the Alpha Quadrant.
History books show many fascinating records of the Menthar's innovative battle strategies. They were the first to use the Kavis Teke elusive maneuver as well as the Passive Lure stratagem which was comparable to the strategies of Napoléon Bonaparte. They also developed a way to modify aceton assimilators to create a booby trap for starships. Both a Promellian battle cruiser and the USS Enterprise-D became ensnared in the trap the Menthars set. (TNG: "Booby Trap")
Geordi La Forge recalled the time they were caught in the Menthar trap to Guinan, in 2367, a year after the event, when he described to her his infatuation with a hologram of Leah Brahms. (TNG: "Galaxy's Child")