Roy G. Richmond, 86, an entomologist with the Department of Agriculture from 1938 until his retirement in 1964, died of congestive heart failure Oct. 5 at Montgomery General Hospital.

He was state entomologist of Colorado for two years before moving here to work for Agriculture's Bureau of Entomology and Plant Quarantine. He received the department's Superior Service Award.

Mr. Richmond was born in Perth, Ontario. During World War I, he served in the Canadian Army in Europe. His decorations included the British Military Medal and the King's Medal.

A graduate of Ontario Agricultural College, he earned a master's degree from Colorado State College, and was an instructor in entomology at Texas A&M College. He became a naturalized citizen in 1932.

Mr. Richmond lived in Arlington for many years and had been an elder of Clarendon Presbyterian Church.

In 1968, he moved to Rossmoor Leisure World in Silver Spring, where he was president of the Kiwanis Club and was active in the development of the Interfaith Chapel and the Fireside Forum.

His wife, the former Ruth Powell, died in 1973.

He is survived by two daughters, Ruth Jane Barth of Rockville, and Jean Willis of Olmsted Falls, Ohio; a son, George, of St. Cloud, Minn.; a brother, Arthur, of London, Ontario, and 10 grandchildren.