Glimmer was the female tribute from District 1 for the 74th Hunger Games. She was part of the Career pack. When Glimmmer took the bow and arrows from the cornucopia at the beginning of the game she incured the jealousy of Katniss Everdeen. Though indirectly, Katniss kills Glimmer, making her Katniss' first kill of the Games. When Katniss drops the tracker jacker hive on the Careers, Glimmer is right under the tree and gets it the worst. She dies from the stings, and Katniss takes the bow and arrows from her stiff, swollen, lifeless body. At the time Katniss is starting to hallucinate, so she's not sure how much of her account is true.
While training with Gloss and Cashmere before the 3rd Quarter Quell Katniss feels guilty about having killed both the District 1 tributes from her Games.