Tria was a holographic alien woman who had a single cranial ridge on her head and several purple spots.

During his visit to the USS Voyager in 2375, the Kadi ambassador Tomin wished to indulge in the pleasures the starship had to offer and paid a visit to Tom Paris' Chez Sandrine holoprogram. There he spent some time with Tria and her friend Alandra. (VOY: "Someone to Watch Over Me")

Tria was played by background actress Monika Kusley who received no credit for her appearance.
She filmed her scenes on Wednesday 3 February 1999 on Paramount Stage 9 and is listed as "Alien Babe" on the call sheet.
Her dress was also worn by background actress Dene Doucette and by guest actress DonnaMarie Recco in the Star Trek: Enterprise episode "Two Days and Two Nights" and was later sold off on the It's A Wrap! sale and auction on eBay. [1]
Her species was mostly made up using Emi's species' prosthesis, but lacked the ridge below her lower lip.
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