Physician, librarian, economic entomologist and teacher, Harris spent much of his time in Cambridge and the nearby area studying and observing in the field. He is reported as being the first or perhaps the second entomologist to deal with economics. These letters were all written to John L. LeConte and deal entirely with the collection and identification of Coleoptera.

These came to the Academy as part of the LeConte family collection identified under Coll. 28.