Funeral services were held Tuesday;Sept.29;1987;for Thelma M.Mackey of Youngstown;formerly of Monessen and Belle Vernon;who died Monday;Sept.28;1987;in Youngstown.  She was 84.  Mrs.Mackey was born June 21;1903;in Cumberland;Md.;a daughter of the late Samuel S.and Ida M.Gallie Siple.  In addition to her parents;she was preceded in death by her husband;Earl S.Mackey;February 1975;a sister;Alma Siple;1930;and a brother;Benjamin Siple;1978.  She was a member of the United Methodist Church of Monessen.  Mrs.Mackey is survived by a sister;Mrs.Melvin A.(Jane) Johnston of Belle Vernon.  Chapel services were held in Monessen at 1 p.m.with the Rev.Kenneth J.Peters officiating.  Burial followed in Belle Vernon Cemetery.