Peeta: “I have kept track of the boy with the bread.” (THG)
Kisses:
Prim: “‘Come on, let’s eat,’ I say and plant a quick kiss on the top of her head.” (THG)
Peeta: “I pull the sleeping bag up to his chin and kiss his forehead, not for the audience, but for me.” (THG)
Hair touching:
Prim: “Prim comes and sits on the floor next to me, leaning her head against my knee. We suck on peppermints as I brush her soft blond hair back behind her ear.” (Catching Fire)
Peeta: “‘Katniss,’ he says. I go over to him and brush the hair back from his eyes. ‘Thanks for finding me.’” (THG)
Bed sharing:
Prim: “When I wake up, the other side of the bed is cold. My fingers stretch out, seeking Prim’s warmth but finding only the rough canvas cover of the mattress. She must have had bad dreams and climbed in with our mother.” (THG)
Peeta: “Then he climbs into bed to hold me until I fall back to sleep. After that, I refuse the pills. But every night I let him into my bed.” (CF)
Going into a hunger games with the intent to save their lives:
Prim: “With one sweep of my arm, I push her behind me. ‘I volunteer!’ I gasp. ‘I volunteer as tribute!’” (THG)
Peeta: “But I have a mission. No, it’s more than a mission. It’s my dying wish. Keep Peeta alive.” (CF)
Katniss’s reactions when she knows/believes them to be dead (or as good as):
Peeta: “I give up. Stop speaking, responding, refuse food and water. They can pump whatever they want into my arm, but it takes more than that to keep a person going once she’s lost the will to live. I even have a funny notion that if I do die, maybe Peeta will be allowed to live.” (Catching Fire)
Prim: “One day I awake to expectations and know I will not be allowed to live in my dreamland. I must take food by mouth. Move my own muscles. Make my way to the bathroom… The doctors’ puzzlement grows over why I’m unable to speak. Many tests are done, and while there’s damage to my vocal cords, it doesn’t account for it. Finally, Dr. Aurelius, a head doctor, comes up with the theory that I’ve become a mental, rather than physical, Avox. That my silence has been brought on by emotional trauma. Although he’s presented with a hundred proposed remedies, he tells them to leave me alone.” (Mockingjay)
We know from the first chapter of the first book that Prim is “the only person in the world I’m certain I love” (THG), and these parallels are put in place because this is what it looks like when Katniss Everdeen truly, deeply loves someone. These are the two people that she loves the most in the world: her sister and her lover/husband-to-be.