Rita DeMara, introduced in Avengers #264, was a reluctant supervillainess who was most notable for her brief affiliation with two incarnations of the Masters of Evil. She had stolen one of Henry Pym's Yellowjacket costumes, and modified it, making it more feminine (and removing the insect emblem). She was awarded temporary reserve member status in the Avengers when she assisted Captain America during a crisis.

When her second affiliation with the Masters of Evil ended, she went to the 30th century with the time travelling Guardians of the Galaxy, and proved her worth when she saved the life of Charlie-27 by shrinking, flying inside his throat, and performing "surgery" on a massive blood clot with her stings. She formed a close friendship with Nikki. She later used 30th century technology to redesign her costume, making it look less like Henry Pym's design (she even found a way to fly without installing wings on her costume).

She used her powers as a valued member of the team, until, homesick, she attempted to return to the 20th Century. On the way, she stopped in the near future and learned that a disaster was about to happen to the Avengers in her target time. When she returned to the present to warn them, she was killed by Iron Man, who was being mind controlled by Immortus in the guise of Kang the Conqueror.