Number of Specimens SD = Standard Deviation
SE = Standard Error C/V = Coefficient of Variation

/========================================================================\
| ~Population~ | No. | Range | Mean | SD | SE | C/V |
|--------------------------+-----+-----------+------+------+------+------|
|_sacki sacki_ | | | | | | |
| Entire Sample | 72 |0.101-0.205| 0.154| 0.052| 0.006| 0.073|
| Puebla: Tehuitzingo | 12 |0.140-0.205| 0.169| 0.052| 0.015| 0.433|
| Guerrero: Chilpancingo | 16 |0.120-0.192| 0.157| 0.021| 0.005| 0.131|
| Guerrero: Mexcala | 21 |0.142-0.180| 0.159| 0.031| 0.007| 0.147|
| Morelos | 23 |0.101-0.180| 0.137| 0.023| 0.005| 0.100|
| | | | | | | |
|_sacki zweifeli_ | | | | | | |
| Entire Sample | 105 |0.064-0.157| 0.097| 0.070| 0.007| 0.067|
| Michoacan: Tafetan | 21 |0.103-0.157| 0.128| 0.039| 0.009| 0.186|
| Michoacan: Apatzingan | 84 |0.064-0.126| 0.089| 0.051| 0.005| 0.060|
| | | | | | | |
|_sacki occidentalis_ | 50 |0.086-0.183| 0.130| 0.021| 0.003| 0.042|
\========================================================================/

From the geographically adjacent populations of _sacki_ (_sacki_ and
_occidentalis_), _zweifeli_ differs in coloration and scutellation
(see Tables I-III). _Cnemidophorus sacki sacki_ has a dorsal pattern
in adult males of dark brown cross-bars on a tan ground-color. Both
_occidentalis_ and _zweifeli_ have variable, diffuse color patterns
in large adults, but _zweifeli_ differs from _occidentalis_ in having
a blue spot on the pink throat.

_Ecology._--In the arid Tepalcatepec Valley _Cnemidophorus sacki
zweifeli_ lives at elevations of 160 to 1300 meters. In the lower
parts of the valley the lizards live primarily in open scrub forests,
characterized by deciduous trees offering only partial shade from the
sun, especially during the prolonged dry season. Common trees in
this scrub forest are _Acacia cymbispina_, _Cercidium
plurifoliolatum_, _Mimosa distachya_, and _Prosopis juliflora_.

During the dry season (November through May) adult males apparently
aestivate; several large series collected in the winter include only
subadults and females. This absence of m