U.S. zoologist noted for his definitive work on termites (termite) and his contributions to biological systematics, the study of the evolutionary and genetic relationships among life forms and their phenotypic similarities and differences.

Emerson conducted extensive field studies of termites in Africa and South America, particularly those of the family Termitidae (the most advanced termite group), and discovered various new genera. He also devoted considerable work to the tertiary fossil species of the family Rhinotermitidae, a group of subterranean termites. In addition, he developed a method of termite phylogenetic inference (i.e., identifying the directions and relative evolutionary rates of certain traits of organisms) by means of the nest characteristics of the genus Apicotermes.