1066 The American Naturalist. [December, 
THE COLOR VARIATIONS OF THE MILK SNAKE. 
By E. D. Cops. 
The Milk Snake, Ophibolus doliatus Linn., ranges in North 
America over the Eastern, Central and Austroriparian dis- 
tricts, and is absent from the Sonoran and Pacific districts, 
It is found also in the humid regions of Mexico and Central 
America, as far as the Isthmus of Darien. Beyond this point 
it does not occur, but a very similar snake (Opheomorphus 
mimus) is found in New Grenada. 
I have called attention to the color variations of this species 
in a brief paragraph in the introduction to my check list of 
Batrachia and Reptilia of North America, 1875' and have 
given the characters of the color types, or subspecies, in an 
analytical key, in a Review of the Characters and Variations 
.of the Snakes of North America, 1892? It is only now possi- 
ble to give a series of figures representing the North American 
color forms ; a possibility for which I am indebted to the U. S. 
National Museum. Both Jan and Bocourt have given admir- 
able figures of some of these, but they have thoroughly con- 
fused the nomenclature? 
The variations of this species are instructive as illustrations 
of the law of variation, in view of the question raised by the 
Neodarwinian school as to its promiscuous or definite charac- 
ter. Are variations multifarious or promiscuous as alleged by 
that school, or do they display a serial passage from a point of 
departure to a definite goal, as alleged by the Neolamarckians? 
Researches into the color forms of insects, as those by Eimer in 
Lepidoptera, and Horn in Coleoptera* point to definite series 
of stages, and my own examination into the color patterns of 
! Bulletin of U. S. National Museum, No. I, p. 4. 
"Proceedings of the U. S, National Museum, XIV, p. 589—608. 
*See memoir quoted at ? for my synonymy. 
*D. Artbildung u. Verwandschaft bei Schmetterlinge, Jena, G. Fischer, 1889. 
5 Proceedings of the American Entomological Soc. 
