R. Zweifel 1953 Masticophis flagellum 3 mi S El Oase (45mi N Hermosillo), Sonora, Mexico 2591 R2 July 20 Seen crawling off the highway at 5:30 PM. The heat of the sun was slightly alleviated by some clouds. Anterior 2/3 of the body black, posterior red. In the black area there are traces of red rings reminiscent of the paired white rings present on the red background of the rare (cognatum) which Jane and Woodin are describing from Motezuma.