ON IN SCUTELLATION IN THAMNOPHIS DORSALIS.

+---------------------------------+-------+---------+------------+
| Character |Mexican|Sierra de|Tepalcatepec|
| |Plateau|Coalcoman| Valley |
+------------------+--------------+-------+---------+------------+
| Ventrals | Female N | 31 | 2 | 32 |
| | Mean | 164.0 | 156.5 | 144.6 |
| | Range|153-171| 154-159 | 138-151 |
| +--------------+-------+---------+------------+
| | Male N | 19 | 2 | 32 |
| | Mean | 153.5 | 154.7 | 138.3 |
| | Range|149-159| 149-159 | 131-141 |
+------------------+--------------+-------+---------+------------+
| Caudals | Female N | 28 | 2 | 29 |
| | Mean | 83.8 | 81.0 | 73.4 |
| | Range|80-100 | 79-83 | 70-79 |
| +--------------+-------+---------+------------+
| | Male N | 14 | 2 | 28 |
| | Mean | 78.0 | 72.0 | 68.5 |
| | Range| 71-87 | 72 | 63-73 |
+------------------+--------------+-------+---------+------------+

One specimen from Uruapan (1550 meters) and one from Coalcoman (950
meters) are intermediate in color pattern between _T. dorsalis cyclides_
and _T. dorsalis postremus_. Both have indistinct lateral stripes and
only small dark spots below the stripes. In scutellation these specimens
are like _T. dorsalis cyclides_.

In Michoacan _Thamnophis dorsalis cyclides_ has been collected in a
variety of habitats on the Mexican Plateau: pine-oak forest, fir forest,
marshes, and cleared land from 1550 to 2800 meters. In the Sierra de
Coalcoman one was taken in broad-leafed forest at 950 meters, three in
pine-oak forest at 2100 meters, and one in pine forest at 2300 meters.

~Thamnophis dorsalis postremus~ Smith

_Thamnophis eques postremus_ Smith, Zoologica, 27:109,
October 23, 1942.--El Sabino, Michoacan, Mexico.

_Thamnophis cyrtopsis postremus_ Smith, Copeia, no. 2:140,
June 8, 1951.

_Thamnophis cyrtopsis cyclides_ (part), Milstead, Texas
Jour. Sci., 5:368, September, 1953.

_Thamnophis dorsalis postremus_, Fitch and Milstea