 Harris' study of insects was a result of his having interacted with William D. Peck while a student at Harvard.Harris lectured on various topics related to his work as a naturalist while he was Harvard librarian, and originated the Harvard Natural History Society for the students.In 1837 he was appointed one of the commissioners for a zoological and botanical survey of Massachusetts, the result of which was his "Systematic Catalogue of the Insects of Massachusetts" in which 2,350 species are enumerated.