LOWELL -- Mary D. (Duffy) Flanagan, 81, a lifelong resident of Lowell, and was a member of St. Anthony Church, died Thursday, April 20, at Wentworth Nursing Care Center in Lowell, after a brief illness.She was the wife of James H. Flanagan, who died in 1987.She was born in Lowell, July 27, 1924, daughter of the late Catherine Duffy, and educated in the local schools.Mrs. Flanagan was a well known resident of Lowell's Back Central neighborhood.She formerly worked in the Lowell Mills.Mrs. Flanagan was a devoted communicant of the former St. Peter Church and the former Sacred Heart Church. She was a communicant of St. Anthony Church.She enjoyed reading and watching television.She is survived by a son, Jimmy P. Flanagan of Lowell; and a cousin and devoted friend, Madeline Reynolds of Lowell.