BELMONT, Mass. — Services were held here late last month for John Martin Mugar, the former chairman of Star Market Co. in New England. He was 92 and died of natural causes. During his more than 40 years at Star, which is now owned by Supervalu, Minneapolis, Mugar was at the forefront of several industry innovations, including adding in-store floral departments and book sales. He also was active in seeking to attract women and minorities to the industry, and founded a program that brought European and African citizens to work in the stores as interns. He retired from the chain in 1978, when it had 61 locations. In addition to his wife, Helen Gienandt Mugar, he is survived by four children, seven grandchildren and two sisters.