Also, it appears to be a seiyuu parody of Maria's voice actress Tanaka Rie, who played Valhalla head catgirl maid Sanada-san (Ms. Sanada) in UFO Princess Valkyrie (aka UFO Ultramaiden Valkyrie), and her penchant for costume playing - just as episode 35 was, with Maria dressing up as Suigintou from Rozen Maiden, another Tanaka Rie character, and Ayanami Rei from Evangelion.
In her
10th Anniversary Birthday Live Concert held on Sunday, January 27, 2008 in Tokyo, Japan, Tanaka Rie sported cat ears (nekomimi). If I recall correctly, she did a similar thing and cosplayed as Sanada-san in a series of three live concerts back in 2003.