The paravertebral stripes begin anteriorly on the nape or at any point on the anterior one-third of the body and continue as discrete stripes onto the base of the tail. Anteriorly these stripes are always broken into a series of dashes; posteriorly the stripes are continuous. In specimens in which the paravertebral stripes do not begin on the anterior-most part of the body, there is no paravertebral pigmentation anteriorly.
In addition to the paravertebrals, the other dorsal dark stripes are variable. In some specimens the stripes are present anteriorly and gradually disappear near mid-body (the first dark stripe only on three specimens). In other specimens the stripes are present anteriorly as dashes and become continuous at mid-body; in others the stripes are continuous throughout. Posteriorly continuous stripes are of uniform width; anteriorly sometimes they are wide on the tip of each scale and narrow on the base ([fig. 1, F]). The variation in continuity and width described above is found in all of the dorsal dark stripes.
The ventrals usually have more or less conspicuous dark spots laterally; in some specimens there are no spots. Except for the dark lateral spots, when present, the ventrals are immaculate white. Usually the dorsal ground-color is a pale tan, especially between the first and second, and the third and fourth dark stripes. The areas between the second and third dark stripes and across the dorsum between the fourth stripes on each side are pale brown. In some specimens the dorsum between the paravertebral stripes is still paler brown.
Never is more than the lower third of the supralabials brown. Many specimens have little brown, and others none. In most of those specimens having brown on the supralabials, the chin and infralabials are dusky tan or gray. There is little or no brown on the supralabials or the chin in the northern part of the range (Chiapas), whereas the greatest amount of brown on the labials and chin is found on some specimens from the southern part of the range (Honduras). Since there is considerable variation in the amount of brown on the chin and labials of specimens from single localities, the slight geographic trend in this character seemingly is not significant.
In juveniles six black or dark brown stripes boldly contrast with a white or pale tan ground-color. At mid-body the first pair of dark stripes is on the 1st scale row; the second pair on the 3rd and 4th rows; the third pair on the 7th, 8th and at least the lower half of the 9th rows ([fig. 3, B]). Ontogenetic change in coloration consists of the splitting of the second and third pairs of dark stripes in the juvenile. The first stripe does not split. Consequently adults have ten dark stripes.
In life an adult from Tonalá, Chiapas, had black stripes. The ground-color below the second stripe, and between the third and fourth dark stripes was tan. The area between the second and third dark stripes was reddish-brown, as was the dorsum between the fourth pair of dark stripes, except that the 10th scale-row was paler.
Three excellent photographs of this species have been published under the name Conophis lineatus (Ditmars, 1931:pls. 26 and 27).
Remarks.—Smith (1941:121-122) described C. pulcher plagosus from Tonalá, Chiapas, and characterized the subspecies by its having "(1) the ventrals completely unspotted; (2) secondary lines on paravertebral rows not continuous posteriorly; (3) all other lines on body also somewhat spotted in appearance; (4) dusky markings on chin and supralabial border very dim (less distinct than in p. pulcher or any member of the lineatus series)." Although all Chiapan specimens lack ventral spots, specimens from Guatemala have no spots, small spots, or large spots. Even in specimens from Tegucigalpa, Honduras, the southernmost limit of the range, the spotting varies from a few inconspicuous spots to many large spots. Paravertebral rows were continuous posteriorly in alimens examined by me. Likewise, all other stripes were continuous bands of uniform width posteriorly, having appeared anteriorly as rows of spots or dashes. The amount of brown on the chin and labials has been shown previously not to be geographically significant. The absence of characters of adequate significance to separate populations precludes the naming of subspecies in this species.
Mertens (1952a:93, and 1952b:61-62) designated three specimens from El Salvador as C. pulcher plagosus. In the latter paper, Mertens, on the basis of a description of a specimen of "C. lineatus" from Divisadero, El Salvador, given by Schmidt (1928:200), referred that specimen also to C. pulcher plagosus. I have examined this specimen and refer it to C. lineatus dunni. Although I have not seen Merten's specimens, on the basis of the excellent descriptions given by Mertens (1952b:61-62), I refer the three Salvadoranean specimens to C. lineatus dunni.
The presence of paravertebral stripes in combination with the characteristics of the genus distinguish Conophis pulcher from all other snakes in southern México and Central America. The only sympatric species of this genus, C. lineatus dunni, differs in that it lacks paravertebral stripes, although it may have a single vertebral stripe. Conophis lineatus dunni has lateral dark stripes that are present on the 3rd and 4th scale-rows, never on the anterior third of the body as in C. pulcher. Even in juveniles the third pair of dark stripes includes the lower part of the 9th scale-row in C. pulcher, whereas the dorsal most dark stripe of C. lineatus dunni never includes more than the lower part of the 8th scale-row.