130 miles south and a little east of the type locality in Nebraska. These probably differ but little from typical specimens. The range of individual variation in pattern is especially notable. In those from the Reservation, the ground color varies from dull olive-brown to almost jet black. The markings on the dorsolateral area vary in color, in shade and in extent. These marks are chiefly confined to the skin between the scales of rows three to nine. Although most typically these marks are of some shade of red (hence the name "red-sided garter snake"), they may be pale buff, or pale greenish yellow, or may even have a bluish tint. In approximately ten per cent of the specimens from the Reservation there is no red at all in the pattern, which hence is similar to that of T. s. sirtalis in the eastern United States. Only a minority have all the dorsolateral marks red, and in some of these specimens the marks higher on the sides are progressively paler red, having a bleached out appearance. Most typically the marks between rows three to six are some shade of red while the smaller marks between rows six to nine are pale—yellowish, greenish, or buffy. In some the pale area of the lateral stripe is in varying degrees suffused with red, which may extend onto the edges of the ventrals and even to the underside of the tail.

T. s. parietalis may be diagnosed, on the basis of these snakes from northeastern Kansas, as follows: Size medium large (length 23.5 to 34.5, or, exceptionally 43.5 inches in adult males; 32.5 to 46.0 inches in adult females), dorsolateral color olive to black. Approximately every other scale of the third row is bordered above and anteriorly by a crescent-shaped area of scarlet colored skin. Similar crescent-shaped areas border the scales of the fourth and fifth rows and often two adjacent crescents meet at the ends of an intervening scale and fuse forming an H-shaped mark. Placed alternately with these markings are similar but smaller crescent-shaped markings on the skin of the upper half of the dorsolateral area on each side bordering every other scale of the sixth, seventh and eighth rows. The crescents of this upper series also may fuse to form series of H-shaped markings alternating with those of the lower series. The dorsal stripe is yellow with a faint dusky suffusion; it involves all of the middorsal scale row and approximately the adjacent half of the row on either side. The lateral stripe is faint, yellowish gray, chiefly on the upper half of the second scale row, lower half of third, and the intervening skin, and is often invaded or suffused by the red marks of the dorsolateral area. The first scale row, adjacent corners of the ventrals, and lower half of the second scale row are suffused with dark pigment and appear dusky, but this area is often marked with black, setting off the paler area of the lateral stripe. The ventrals are dull, whitish, faintly suffused with yellowish, greenish or bluish, each ventral having a black dot usually of semicircular shape on its anterior margin near the anterolateral corner.

Comparison of T. s. parietalis and T. s. fitchi

Like most widely ranging subspecies, parietalis and fitchi vary geographically and local populations often are noticeably different from typical material. It is possible that future revisors will recognize additional subspecies, but in the variant populations known to us the degree of differentiation is slight as compared, for instance, with that in the subspecies of Thamnophis elegans. Scalation is remarkably uniform in all the subspecies of sirtalis, but coastal and northern populations tend to have fewer ventrals and subcaudals than do their counterparts farther inland and farther south. In their geographic variation the ventrals and subcaudals follow clines, and do not in themselves warrant subspecific divisions. Variation occurs chiefly in the color and pattern including the intensity of dark pigmentation of the dorsolateral area, head, ventral surface and lower edge of the lateral stripe; in extent, position and shade of red or pale colored markings on the dorsolateral area; in presence and extent of reddish suffusion on the head, in the region of the lateral stripe, and on the ventral surface of the tail. Most of these same characters vary within the subspecies fitchi, but the range of variation is relatively minor. Fitch (op. cit.:582-584) described typical populations and also described briefly several small series from British Columbia, Idaho, Oregon, and California which were not entirely typical. Most frequent variation was in heavy reddish suffusion on the sides of the head not found in typical fitchi. In each local population of this subspecies the characters seem to be remarkably uniform and stable.

Fig. 2. Diagrammatic drawing of pattern in stretched skin of T. s. fitchi; the pale markings on the black dorsolateral area are scarlet (× 2-1/2).

Fig. 3. Diagrammatic drawing of stretched skin of T. s. parietalis; the scarlet markings extend farther dorsally than in T. s. fitchi and black spots are prominent on the ventrals laterally. Some individuals of parietalis have much paler ground color, resembling ornata except in minor details (× 2-1/2).

Fig. 4. Diagrammatic drawing of stretched skin of T. s. ornata. The ground color is like that of parietalis but paler with a continuous black area bordering the dorsal stripe (× 2-1/2).

T. s. parietalis differs from fitchi in several trenchant characters, and there are additional slight or average differences between the two. In approximate order of their importance the differences are as follows: 1) The red (or pale yellow or green or buffy) marks on skin between the scales on the upper half of the dorsolateral area (that is between the sixth and seventh, seventh and eighth and eighth and ninth scale rows) present in parietalis are missing in fitchi or are represented by only an occasional small fleck. 2) The dorsolateral area is black or nearly so in fitchi but averages paler in parietalis, in which a wide range of shades may be found from black to olive brown. 3) The red of the dorsolateral area frequently invades the lateral stripe, which sometimes is mostly red, and may even invade the ventrals in parietalis, but in fitchi the red marks are usually confined to the dorsolateral area, and do not invade the lateral stripe. 4) The prominent paired black dots or semicircular marks on the anterior edge of each ventral in parietalis are largely lacking in fitchi, which rarely has any dark marks on the