Private graveside services for Donald Brooke Creecy Jr., a retired National Security Agency mathematician and former resident of Gibson Island, will be held Tuesday at Arlington National Cemetery.

Mr. Creecy died of pneumonia May 15 at a hospital in Bradenton, Fla., where he was visiting family. He was 76.

A native of Baltimore, he attended the Gilman School and in 1936 was graduated from Princeton University.

Mr. Creecy went to work as a civilian employee of the Defense Department before being called into military service during World War II. He served in the Army in the Marianas Islands.

After the war, he returned to work at the Defense Department and later moved to the National Security Agency, from which he retired in 1970.

In retirement, Mr. Creecy fulfilled a dream of crossing the South ,, Pacific on a freighter.

He lived in England, Spain and Australia before settling in New Haven, Conn.

Mr. Creecy was a member of the Sons of the American Revolution. He also belonged to the Society of Lees of Virginia.

He is survived by his wife of 19 years, Myra Creecy of New Haven, Conn.; four stepchildren, Bernard Joseph Arthur, Susan Michelle Kelly, Lisa Karen Dalesio and Matthew David Arthur, all of Bradenton, Fla.; five grandchildren; and four nephews.