By
HOBART M. SMITH
The chief characters distinguishing Thamnophis radix (Baird andGirard) and T. marciana (Baird and Girard) in southern Kansasare:
| marciana | radix | |
|---|---|---|
| 1. lateral light line involving only the 3d scale row anteriorly. | 1. lateral light line involving rows 3 and 4 anteriorly. | |
| 2. dorsal light line without distinctedges, varying in width from less than 1 to nearly 3 scale rows, at various places on body. | 2. dorsal light line with straight, even edges, 1½ scale rows wide. | |
| 3. several anterior lateral spots fused across lateral light stripes. | 3. usually no anterior lateral spots fused across lateral light stripes. | |
| 4. 2 posterior upper labials not light-centered, unlike others. | 4. 2 posterior labials light-centered, like others. | |
| 5. A well-developed, white, black-edged crescent behind angle of jaws (postrictal crescent). | 5. typically no well-developed postrictal crescent. |
Typical specimens of radix are available from several localities inMorton County of southwestern Kansas (Spring Creek; twelvemiles and eighteen miles north of Elkhart; Elkhart); from the StateLake and Meade in Meade County; from Hunters, Harper County;Coolidge, Hamilton County; and Ingalls, Gray County.
Typical marciana is available from Spring Creek, Morton County;Liberal, Seward County; and Clark County (no locality). An overlapof range with radix is evident, and from Spring Creek in MortonCounty typical specimens of both species are available. Accordingly,at present, I conclude that the two forms are correctly regarded asdistinct species.
Yet there is a rather marked tendency of radix to approach thecharacters of marciana in southwestern Kan