In the short story The Manhood of Edward Robinson, Agnes Larella is a wealthy woman who at the time of the story was staying at a hotel near the Devil's Punch Bowl in Surrey. As part of a "burglary for fun" scheme, Lady Noreen Elliot and her fiance Jimmy were selected by lot to burgle a diamond necklace from her. The theft of the necklace went well but Jimmy, whose job it was to create a diversion, tripped and injured his ankle. So completely unsuspecting was Agnes of the events that she even loaned her chauffeur to drive Jimmy home in his car. At that time, Jimmy was dressed as a woman. Why this aroused no suspicion is a matter for conjecture.
Agnes Larella is mentioned in the story but does not appear in person. She is also mentioned in the episode The Manhood of Edward Robinson of The Agatha Christie Hour, a TV film adaptation of the story, but likewise the character is not cast and does not appear on screen.