There are no apparent hemipenial differences among the species of the genus _Conophis_. As can be seen in the above description, the hemipenis of _C. vittatus_ is less bilobed and has a more pronounced disc at the apex than the others. The hemipenis of _C. lineatus concolor_ is most bilobed, but has the smallest apical disc. The other species and subspecies vary widely within these extremes. Food and Feeding _Conophis_ eats mostly small lizards, especially _Cnemidophorus_. In México _Conophis_ occurs in semi-arid habitat where _Cnemidophorus_ is common. A specimen each of _Conophis vittatus_ and _C. lineatus lineatus_ were obtained while I was collecting _Cnemidophorus_. The only record of _Conophis_ having fed on a warm-blooded vertebrate was obtained in the course of this study, when I recovered from the stomach of a _Conophis lineatus concolor_ (CNHM 36299) from Chichén Itzá, Yucatán, a heteromyid rodent (_Heteromys gaumeri_). Ralph Axtell (personal communication) observed _Conophis_ actively searching for food at dusk. His observations were made near Tehuantepec, Oaxaca, and the snakes were seen to chase lizards of the genus _Cnemidophorus_. Near Alvarado, Veracruz, in the late afternoon, I watched a _Conophis lineatus lineatus_ follow a lizard into a hole. Mittleman (1944:122) presents the only discussion of the mode of feeding of a captive specimen of _Conophis lineatus_ ssp. When presented with a _Thamnophis_ slightly smaller than itself, the _Conophis_ struck, and within eight minutes immobilized the _Thamnophis_. Within one-half hour the _Thamnophis_ was swallowed. Three days later the _Conophis_ ate another _Thamnophis_, though still distended from its first meal; nine days later it ate a _Storeria_. In the course of several months, the _Conophis_ ate various toads and hylids and two more _Storeria_. Apparently members of the genus _Conophis_ do not constrict their prey, but rely upon a combination of loss of blood and action of the venom to completely immobilize their prey. Ditmars (1931:pls. 26-27) showed three photographs of "_Conophis lineatus_" (actually _Conophis pulcher_) ingesting another snake, identified by him as a young _Ophis (= Xenodon) colubrinus_. Effect of Poison