the listing of the San Francisco garter snake in 1967 continue to affect the subspecies. These environmental elements include loss of habitat from agricultural, commercial and urban development, as well as collection by reptile fanciers and breeders. Collection of these endangered animals by private citizens remains illegal. References Further reading Behler JL, King FW (1979). The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. . (Thamnophis sirtalis tetrataenia, p. 676 + Plate 541). Cope ED (1875). In Yarrow HC (1875). Report upon the Collections of Batrachians and Reptiles made in Portions of Nevada, Utah, California, Colorado, New Mexico, and Arizona, during the Years 1871, 1872, 1873, and 1874. Chapter IV. Washington, District of Columbia: United States Government. pp. 509–584. (Eutaenia sirtalis tetratænia, new subspecies, p. 546). Smith HM, Brodie ED Jr (1982). Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. . (Thamnophis sirtalis tetrataenia, pp. 148–149). Stebbins RC (2003). A Field Guide to Western Reptiles and Amphibians, Third Edition. The Peterson Field Guide Series ®. Boston and New York: Houghton Mifflin Company. xiii + 533 pp. . (Thamnophis sirtalis tetrataenia, pp. 376–377 + Plate 48 + Map 162). Wright AH, Wright AA (1957). Handbook of Snakes of the United States and Canada. Ithaca and London: Comstock Publishing Assosciates. 1,105 pp. (in two volumes). (Thamnophis sirtalis tetrataenia, pp. 861–863 + Figure 248 + Maps 59, 60). Thamnophis Endemic fauna of California Fauna of the San Francisco Bay Area Natural history of San Mateo County, California Natural history of Santa Cruz County, California Reptiles of the United States Endangered fauna of California ESA endangered species