deMONTIGNY, Mary Z. (Louder) Of Lexington, April 22, 2013. Wife of the late William G. deMontigny Sr. Mother of Mary Joanne Ulloa and her husband Francisco of Watertown, Janet Moran of Lexington, and William G. deMontigny Jr. of Arlington. Sister of Alice Patricia Riordan of Greenville, RI. Grandmother of Alexander Ulloa, Kate Davis, Beth Veatch, Susan Smedley, and Vickie Lee Porter. Mary is also survived by 8 great grandchildren and by her special friends Michelle and Mike McCann. Funeral from the Douglass Funeral Home, 51 Worthen Rd. Lexington Friday April 26 at 9am followed by a Mass of Christian burial at St. Brigid Church, Lexington at 10am. Relatives and friends are kindly invited to attend. Visiting hours Thurs. from 4-8pm. Donations in her memory may be made to the Home For Little Wanderers, 271 Huntington Ave., Boston, MA 02115. Interment Oak Grove Cemetery, Medford.