Pilot Snake (Coluber obsoletus: Jordan, David Starr. 1876. Manual of the Vertebrates of the Northern United States: Including the District East of the Mississippi River, and North of North Carolina and Tennessee, Exclusive of Marine Species. Jansen, McClurg, and Company, Chicago, Illinois.. 342pp.); Racer (Coluber obsoletus obsoletus: Yarrow, Henry C. 1876. List of Skeletons and Crania in the Section of Comparative Anatomy of the United States Army Medical Museum for use during the International Exhibition of 1876 in Connection with the Representation of the Medical Department U.S. Army. Army Medical Museum, Washington, D. C. pp.); Pilot Black Snake (Coluber obsoletus obsoletus: Yarrow, Henry C. 1876. List of Skeletons and Crania in the Section of Comparative Anatomy of the United States Army Medical Museum for use during the International Exhibition of 1876 in Connection with the Representation of the Medical Department U.S. Army. Army Medical Museum, Washington, D. C. pp.); Pilot Snake (Coluber obsoletus: Jordan, David S. 1878. Manual of the Vertebrates of the Northern United States: Including the District East of the Mississippi River, and North of North Carolina and Tennessee, Exclusive of Marine Species. Second Edition, Revised, and Enlarged. Jansen, McClurg & Company, Chicago. pp.); Racer (Coluber obsoletus: Jordan, David S. 1878. Manual of the Vertebrates of the Northern United States: Including the District East of the Mississippi River, and North of North Carolina and Tennessee, Exclusive of Marine Species. Second Edition, Revised, and Enlarged. Jansen, McClurg & Company, Chicago. pp.); Lindheimer's Snake (Coluber lindheimeri: Yarrow, Henry C. 1882. Check list of North American Reptilia and Batrachia with catalogue of specimens in U. S. National Museum. Bulletin of the United States National Museum (24):1-249); Mountain Black Snake (Coluber obsoletus obsoletus: Yarrow, Henry C. 1882. Check list of North American Reptilia and Batrachia with catalogue of specimens in U. S. National Museum. Bulletin of the United States National Museum (24):1-249); Pilot Snake (Coluber obsoletus obsoletus: Davis, N. S. Jr. and Frank L. Rice. 1883. Descriptive catalogue of North American batrachia and reptilia, found east of Mississippi River. Illinois Natural History Survey Bulletin 1(5):71); Black Snake (Elaphis obsoletus: Garman, H. 1892. A synopsis of the reptiles and amphibians of Illinois. Illinois Laboratory of Natural History Bulletin 3():215-403); Pilot Snake (Elaphis obsoletus: Garman, H. 1892. A synopsis of the reptiles and amphibians of Illinois. Illinois Laboratory of Natural History Bulletin 3():215-403); Pilot Snake (Coluber obsoletus: Cope, Edward D. 1900. The crocodilians, lizards and snakes of North America. Pages 153-1270 in Report of the U. S. National Museum for the Year Ending June 30, 1898 , Washington, D. C. pp.); Mountain Black Snake (Coluber obsoletus: Cope, Edward D. 1900. The crocodilians, lizards and snakes of North America. Pages 153-1270 in Report of the U. S. National Museum for the Year Ending June 30, 1898 , Washington, D. C. pp.); Black Chicken Snake (Coluber obsoletus obsoletus: Beyer, George. 1900. Louisana herpetology. Proceedings of the Louisiana Society of Naturalists 1897-1899():24-46); Red-headed Chicken Snake (Coluber spiloides: Beyer, George. 1900. Louisana herpetology. Proceedings of the Louisiana Society of Naturalists 1897-1899():24-46); Lindheimer's Snake (Coluber obsoletus lindheimeri: Brown, Arthur, E. 1902. Report of the Board of Directors. Pages 5-22 in Thirtieth Annual Report of the Board of Directors of the Zoological Society of Philadelphia. Allen, Lane, and Scott, Philadelphia, Pennsylvania. pp.); Red-headed Coluber (Coluber spiloides: Branson, Edwin B. 1904. Snakes of Kansas. University of Kansas Science Bulletin 2(13):353-430); Black Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Mountain Black Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Pilot Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Rat Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Pilot Blacksnake (Elaphe obsoleta obsoleta: Stejneger, Leonard and Thomas Barbour. 1917. A Checklist of North American Amphibians and Reptiles. Harvard University Press, Cambridge, Massachusetts. pp.); Chicken Snake (Elaphe obsoleta confinis: Strecker, John K. 1922. An annotated catalogue of the amphibians and reptiles of Bexar County, Texas. Bulletin Scientific Society of San Antonio (4):1-31); Gray Pilot Snake (Elaphe obsoleta confinis: Strecker, John K. 1922. An annotated catalogue of the amphibians and reptiles of Bexar County, Texas. Bulletin Scientific Society of San Antonio (4):1-31); Lindheimer's Pilot Snake (Elaphe obsoleta lindheimerii: Strecker, John K. 1922. An annotated catalogue of the amphibians and reptiles of Bexar County, Texas. Bulletin Scientific Society of San Antonio (4):1-31); Emory's Rat Snake (Elaphe laeta: Schmidt, Karl Peterson and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365pp.); Pilot Black Snake (Elaphe obsoleta obsoleta: Schmidt, Karl Peterson and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365pp.); Chicken Snake (Elaphe obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Rat Snake (Elaphe obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Texas Chicken Snake (Elaphe obsoleta lindheimeri: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Black Chicken Snake (Elaphe obsoleta obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Pilot Black Snake (Elaphe obsoleta obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.);