The descriptions and discussions in this bulletin have brought out the fact that the genus Lampropeltis is naturally divided into three main groups, of closely related forms (exclusive of two forms of doubtful relationships, mexicana and alterna). Two (the Getulus an Calligaster groups) are more closely allied to each other than either to the third, and the latter (Triangulum group) is composed of at least three minor groups, representing different degrees and kinds of differentiation, and different periods of dispersal.