His 1941 University of Pennsylvania Ph.D. dissertation was an early work highlighting the role phallic structures could play in grasshopper taxonomy.

He described dozens of grasshopper species from North and South America, and also is the eponym of several taxa named in his honor.

[1] His dissertation, A Comparative Study of the Subfamilies of the Acrididae (Orthoptera) Primarily on the Basis of Their Phallic Structures, was published in Proceedings of the Academy of Natural Sciences of Philadelphia.

[18] Roberts volunteered with the U.S. Army during World War II, joining the Medical Entomological Department.

[4] Roberts and Ross began working on this publication at the headquarters of the 8th Service Command in Texas and finished writing it at the U.S. National Museum.

[21] It was important to those fighting malaria during World War II and helped saved thousands of lives.

[24] In order to get the grasshoppers down from the trees he invented a machine to shoot insecticide into the canopy and then dead insects would fall to plastic tarps on the ground.

[28][29] Roberts' papers on Orthoptera were published over the span of 1937 to 1992; fifty-four of the grasshopper species he described remained valid names as of 2009.

[1] As part of his efforts to professionalize the research staff, Roberts recruited scientists from outside Philadelphia for paid positions which previously were often held by self-financed volunteers.

[36] His wife sometimes accompanied him on field expeditions;[15] while in Mexico, she collected the type specimen of Coelostemma hazelae, which the American malacologist Henry Augustus Pilsbry named after her.

[27] He had been planning an expedition to do additional fieldwork in Brazil before he fell ill. Ruth Patrick wrote his obituary for Proceedings of the Academy of Natural Sciences of Philadelphia.

[1] Revista de la Sociedad Entomológica Argentina  [es] also published an obituary of Roberts,[28] as did The Philadelphia Inquirer[27] and Princeton Alumni Weekly.