Characters showing inter-specific and intra-specific variation and that have a wide range of variation were analyzed statistically, when possible, in order to determine extent of variation. One character (see table 3) was analyzed for sexual dimorphism, and for it the coefficient of difference is also given. The statistical terms and formulae have been adopted from Mayr, Linsley and Usinger (1953). Dorsal head shields varied individually and were of no taxonomic importance. Osteological and hemipeneal characters did not show enough variation to be considered here.
Labials, dorsals, ventrals, and subcaudals were the most useful scales.
Labials.—All species usually have eight supralabials except C. vittatus, which has seven. The only other population having a relatively high frequency of occurrence of seven supralabials is C. l. lineatus. In specimens having eight supralabials, the fourth and fifth enter the orbit; in specimens having seven supralabials, the third and fourth enter the orbit (the second and third are fused). Usually there are ten infralabials, sometimes nine or eleven; specimens having seven supralabials usually have nine infralabials, sometimes eight, rarely ten.
Dorsals.—Although there is no variation in the number of rows of dorsal scales, there is some in the method of scale reduction. There are 19 rows of dorsal scales from close behind the head to about midway on the body where two rows are lost, leaving 17 rows from there to near the base of the tail. This reduction is accomplished by fusion of the scales of the 3rd and 4th rows or sometimes by the dropping out of the 3rd row. The place at which reduction occurs in number of dorsal scales in relation to the ventral (scale) directly below is highly variable and of little taxonomic importance (table 1).
Table 1.—Variation in the Place of Dorsal Scale Reduction in Conophis.
| Taxon | Number of Specimens | Range | Mean | Standard Deviation | Standard Error | Coefficient of Variation |
| l. concolor | 45 | 89-114 | 102.5 | 5.57 | 0.83 | 5.43 |
| l. dunni | 36 | 91-111 | 102.1 | 4.59 | 0.77 | 4.50 |
| l. lineatus | 26 | 91-107 | 100.2 | 3.59 | 0.72 | 3.58 |
| nevermanni | 6 | 84- 97 | 93.2 | 4.71 | 1.92 | 5.05 |
| pulcher | 26 | 94-119 | 104.6 | 4.90 | 0.96 | 4.68 |
| vittatus | 170 | 84-118 | 102.3 | 6.60 | 0.16 | 6.45 |
Ventrals.—The number of ventral scutes varies from 149-183, and shows no significant variation in the means (table 2).