Gregg, E. V. 1945. A statistical study of taxonomic categories in ants (Formicidae: Lasius neoniger and Lasius americanus). Annals of the Entomological Society of America 38:529-548. PDF

Gregg, R. E. 1938. [Review of: Wheeler, W. M. 1937. Mosaics and other anomalies among ants. Cambridge, Mass.: Harvard University Press, 95 pp.]. Ecology 19:312-314.

Gregg, R. E. 1942. The origin of castes in ants with special reference to Pheidole morrisi Forel. Ecology 23:295-308.

Gregg, R. E. 1945a ("1944"). The ants of the Chicago region. Annals of the Entomological Society of America 37:447-480. PDF

Gregg, R. E. 1945b. The worker caste of Harpagoxenus canadensis Smith (Formicidae). Canadian Entomologist 77:74-76. PDF

Gregg, R. E. 1945c. Two new forms of Monomorium (Formicidae). Psyche (Cambridge) 52:62-69. PDF

Gregg, R. E. 1946. The ants of northeastern Minnesota. American Midland Naturalist 35:747-755. PDF

Gregg, R. E. 1947. Altitudinal indicators among the Formicidae. University of Colorado Studies. Physical and Biological Sciences 2:385-403.

Gregg, R. E. 1948. An unusual nest of the prairie mound-building ant (Hymenoptera, Formicidae). Proceedings of the Entomological Society of Washington 50:183-186.

Gregg, R. E. 1949a. A note on Pheidole (Macropheidole) rhea Wheeler (Hymenoptera: Formicidae). Psyche (Cambridge) 56:70-73. PDF

Gregg, R. E. 1949b. A new ant from southwestern United States (Hymenoptera, Formicidae). Proceedings of the Entomological Society of Washington 51:171-174. PDF

Gregg, R. E. 1950. A new species of Pheidole from the Southwest. Journal of the New York Entomological Society 58:89-93. PDF

Gregg, R. E. 1951. Two new species of exotic ants. Psyche (Cambridge) 58:77-84. PDF

Gregg, R. E. 1952a. A new ant of the genus Pheidole from Colorado. American Museum Novitates 1557:1-4. PDF

Gregg, R. E. 1952b. The female of Formica opaciventris Emery (Formicidae). Psyche (Cambridge) 59:13-19. PDF

Gregg, R. E. 1953a. Notes on the ant, Leptothorax obliquicanthus Cole (Hymenoptera: Formicidae). Breviora 22:1-4. PDF

Gregg, R. E. 1953b. The soldier caste of Pheidole (Ceratopheidole) clydei Gregg (Hymenoptera, Formicidae). American Museum Novitates 1637:1-7. PDF

Gregg, R. E. 1953c. Morphological considerations affecting the taxonomy of certain genera of ants (Hymenoptera, Formicidae). Proceedings of the Entomological Society of Washington 55:324-330. PDF

Gregg, R. E. 1954a ("1953"). Taxonomic notes on the ant, Camponotus cooperi Gregg. Psyche (Cambridge) 60:102-104. PDF

Gregg, R. E. 1954b. Geographical distribution of the genus Myrmoteras, including the description of a new species (Hymenoptera: Formicidae). Psyche (Cambridge) 61:20-30. PDF

Gregg, R. E. 1955a. A new species of ant belonging to the Pheidole pilifera complex (Hymenoptera: Formicidae). Psyche (Cambridge) 62:19-28. PDF

Gregg, R. E. 1955b. The rediscovery of Veromessor lobognathus (Andrews) (Hymenoptera: Formicidae). Psyche (Cambridge) 62:45-52.

Gregg, R. E. 1956. An extension of range for the ant, Pheidole lamia Wheeler (Hymenoptera: Formicidae). Entomological News 67:37-39.

Gregg, R. E. 1957 ("1956"). A new species of Myrmoteras from Ceylon (Hymenoptera: Formicidae). Psyche (Cambridge) 63:41-45. PDF

Gregg, R. E. 1958. Two new species of Metapone from Madagascar (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington 60:111-121. PDF

Gregg, R. E. 1959 ("1958"). Key to the species of Pheidole (Hymenoptera: Formicidae) in the United States. Journal of the New York Entomological Society 66:7-48. PDF

Gregg, R. E. 1961. The status of certain myrmicine ants in western North America with a consideration of the genus Paramyrmica Cole (Hymenoptera: Formicidae). Journal of the New York Entomological Society 69:209-220. PDF

Gregg, R. E. 1963. The ants of Colorado, with reference to their ecology, taxonomy, and geographic distribution. Boulder: University of Colorado Press, xvi + 792 pp.

Gregg, R. E. 1964. Distribution of the ant genus Formica in the mountains of Colorado. Leaflet. University of Colorado Museum 13:59-69.

Gregg, R. E. 1969a. Geographic distribution of the ant genus Formica (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington 71:38-49. PDF