The image below is from Amphibian and Reptile Atlas of Peninsular California 1996.
It seems to be a great new website. Below is Pituophis insulanus from that site.
See this image from the site above
Chris Mattison image
CEDROS ISLAND GOPHER SNAKE Topera de Isla Cedros
Pituophis (melanoleucus-catenifer) insulanus ( Klauber, 1946 )
(See this site on this snake.) http://www2.inecc.gob.mx/publicaciones/libros/536/anfibios.pdf (See page 35 for nice live snake image and information.)
Photo by Patrick Houston Briggs Courtesy San Diego Natural History Museum (Obviously Preserved)
The Cedro Island Gopher Snake Pituophis insulanus (formely P. melanoleucus insulanus) gets its scientific name from the Latin word insul meaning "island" and anus meaning "to belong to". Respectively it is indigenous only to an island known as the Isla De Cedro or (Cedros Island) south of the San Martin Island that also, is off the coast from Guerrero Negro of Baja California. In the latter 1990's, it was argueably elevated to full species status. Using an evolutionary species concept, Grismer elevated Pituophis insulanus of Isla de Cedros to full species, because it showed no overlap in diagnostic characteristics with Pituophis vertebralis. This diurnal snake has many more markings than vertebralis of Baja California. Called the Topera de isla Cedros in Baja Mexico, it grows to about a length of 116.2 cm. The dorsal ground color is yellowish-red with black blotches which seem to become more narrow toward the rear. The spots along each side are also black. It has large eyes with round pupils on a head which is just slightly wider than the neck. Its body is somewhat cilindrical and muscular with keeled scales on the uppermost rows. The Cedro Island gopher snake is active year round eating small mammals, birds, and probably lizards. It breeds in the spring.
Photo by Patrick Houston Briggs Courtesy San Diego Natural Histoy Museum (Upper Head and Snout Study)
Photo by Patrick Houston Briggs Courtesy San Diego Natural History Museum (Throat and Chin Closeup)
Photo by Patrick Houston Briggs Courtesy San Diego Natural History Museum (Venter Examination)
Photo by Patrick Houston Briggs Courtesy San Diego Natural History Museum (Underbelly of Specimen 2 Preserved)
Photo by Patrick Houston Briggs Courtesy San Diego Natural History Museum (Dorsal Anterior Study Preserved)
Photo by Patrick Houston Briggs Courtesy San Diego Natural History Museum (Dorsal Examination Preserved)
This image is from an excellent book called Amphibians and Reptiles of Baja California
including its Pacific Islands and the Islands in the Sea of Cortes by L. Lee Grismer
Photo below by Chris Mattison
Here's what the cover looks like. Check it out, it's an excellent book.
Below is are 2 images by someone who calls himself "snakeinmypocket" from a nice website called iNaturalist.org