Mariclare Costello Courtesy Everett Collection Share on Facebook Share on X Google Preferred Share to Flipboard Show additional share options Share on LinkedIn Share on Pinterest Share on Reddit Share on Tumblr Share on Whats App Send an Email Print the Article Post a Comment Mariclare Costello, a lifetime member of The Actors Studio who recurred as the schoolteacher Rosemary Hunter on The Waltons and played a hippie vampire in the cult horror film Let's Scare Jessica to Death, died April 17 in Brooklyn, her family announced. She was 90.