University of Kansas Publications

Museum of Natural History

Vol. 10, No. 10, pp. 599-610, 1 pl., 1 fig.

May 2, 1960

A Taxonomic Study

of the Middle American Snake,

Pituophis deppei

BY

WILLIAM E. DUELLMAN

University of Kansas

Lawrence

1960

University of Kansas Publications, Museum of Natural History

Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
Robert W. Wilson

Volume 10, No. 10, pp. 599-610, 1 pl., 1 fig.
Published May 2, 1960

University of Kansas

Lawrence, Kansas

PRINTED IN

THE STATE PRINTING PLANT

TOPEKA, KANSAS

1960

28-2493

PLATE 45

Fig. 1. Pituophis deppei deppei from Cumbres de Acultzingo, Veracruz,
UMMZ 114596. Approx. 1/2 natural size.

Fig. 2. Pituophis lineaticollis lineaticollis from Dos Aguas, Michoacán,
UMMZ 119567. Approx. 1/3 natural size.

A Taxonomic Study
of the Middle American Snake,
Pituophis deppei

BY

WILLIAM E. DUELLMAN

INTRODUCTION

As a part of a study of the herpetofauna of the Mexican state of
Michoacán an attempt was made to ascertain the interspecific and
intraspecific relationships of the various populations of Pituophis
there. Field work in Michoacán revealed that two supposed subspecies
of Pituophis deppei were sympatric. This discovery led to
the examination of all available (124) museum specimens of these
snakes.

I am grateful to the following persons who permitted me to
examine specimens in their care: Charles M. Bogert, American
Museum of Natural History (AMNH); Doris M. Cochran, United
States National Museum (USNM); Norman Hartweg, University
of Michigan Museum of Zoology (UMMZ); Robert F. Inger, Chicago
Natural History Museum (CNHM); Arthur Loveridge, Museum
of Comparative Zoology (MCZ); Hobart M. Smith, University
of Illinois Museum of Natural History (UIMNH); and
Edward H. Taylor, E. H. Taylor—H. M. Smith collection (EHT-HMS).
Specimens in the accounts of the species are listed after
the abbreviations of the institutions given in parentheses above.

HISTORICAL REVIEW

Duméril (1853: 453) described Elaphis deppei from a specimen
in the Leiden Museum from “Mexico.” This specimen, according
to the type description, has 233 ventrals and 67 caudals. In 1863
Jan described Pituophis deppei var. pholidostictus, also with “Mexico”
as the type locality. Subsequent authors (see synonymy of
P. deppei deppei in Stull, 1940: 25) have treated pholidostictus
as a synonym of deppei. Smith and Taylor (1950: 334) restricted
the type localities of deppei and pholidostictus to San Juan Teotihuacán,
México. Cope (1860: 369) described Arizona jani on the
basis of a specimen in the United States National Museum from
Buena Vista, Coahuila. Stull (1932: 2, 1940: 42), Smith (1944:
145) and Smith and Taylor (1945: 107) considered jani as a
northern subspecies of Pituophis deppei. Arizona lineaticollis was
described by Cope (1861: 300); the type, which originally was in
the Academy of Natural Sciences of Philadelphia and is now lost,
was said to have come from Jalapa, Veracruz. This locality probably
is in error. Smith (1943: 460) placed lineaticollis as a southern
subspecies of deppei. Schmidt and Shannon (1947: 79) described
Pituophis deppei brevilineata on the basis of five specimens from
Tancítaro, Michoacán, and Stuart (1954: 172) described Pituophis
deppei gibsoni from seven specimens from Departamento Chimaltenango,
Guatemala. Thus, at present five subspecies of Pituophis
deppei are recognized.

CHARACTERS STUDIED

Snakes currently assigned to Pituophis deppei differ from other
members of the genus by possessing two instead of four prefrontal
plates. The subspecies of P. deppei have been defined on characters
of coloration and scutellation.

Scutellation.—The only scale characters utilized in the present
study are the numbers of ventrals and caudals. The number of
ventrals varies in the total sample from 210 to 246 (Table 1);
usually the variation in one locality is no more than 15. Number
of caudals varies from 52 to 72. There is slight sexual dimorphism
in the number of ventrals and somewhat greater differences in the
number of caudals.

Table 1.—Variation in the Numbers of Ventrals and Caudals
in Four Subspecies of Pituophis.

Coloration.—The dorsal ground color is tan or straw; the dorsal
pattern consists basically of dark middorsal blotches and dark lateral
intercalary spots. Number of blotches, color of blotches posteriorly,
width of pale interspaces between anterior blotches, and
color of lateral intercalary spots vary considerably geographically.
In some populations (lineaticollis and gibsoni) the anterior blotches
are divided medially forming either a pair of dark stripes on the anterior
part of the body or a series of paired spots. Details of coloration
are described in the following accounts.

Fig. 1. México and Guatemala showing the distribution of the subspecies
of Pituophis deppei and P. lineaticollis.

ACCOUNTS OF THE SPECIES AND SUBSPECIES

Study of Pituophis deppei (auctorum) revealed the presence of
sympatric populations of two distinct species of Pituophis differing
from each other in scutellation and coloration. The nomenclature resulting
from the required rearrangement necessitates the recognition
of 1) deppei as a species, 2) jani as a subspecies of deppei, 3) lineaticollis
(with brevilineata as a synonym) as a species distinct from
deppei, and 4) gibsoni as a subspecies of lineaticollis. Known geographic
distributions of these named taxa are shown in Figure 1.

Pituophis deppei deppei Duméril

Elaphis deppei Duméril, Mem. Acad. Inst. France, vol. 23, p. 453, 1853;
Duméril and Bibron, Erpétologie générale, vol. 7, p. 268, February 25,
1854.

Pituophis deppei, Jan, Elenco sistematico degli ofidi, p. 59, 1863; Günther,
Biologia Centrali-Americana, Reptilia, p. 124, February, 1894.

Elaphis pleurostictus Duméril, Mem. Acad. Inst. France, vol. 23, p. 453,
1853 [Type.—Museum d’Histoire Naturelle Paris, No. 6616; type locality—”Monte
Video” (restricted to San Juan Teotihuacán, México, by Smith
and Taylor, 1950: 334)].

Pituophis pleurostictus, Jan, Elenco sistematico degli ofidi, p. 59, 1863.

Pituophis deppei, var. pholidostictus Jan, Elenco sistematico degli ofidi, p.
59, 1863 [Type.—Zoologisches Museum Berlin, No. 1738; type locality.—”Mexico”
(restricted to San Juan Teotihuacán, México, by Smith and
Taylor, 1950: 334)].

Pituophis deppei deppei, Stull, Occas. Papers Mus. Zool. Univ. Michigan,
no. 250, p. 1, October 12, 1932; Bull. U. S. Natl. Mus. 175, p. 25,
April 23, 1940; Smith and Taylor, U. S. Natl. Mus., no. 187, p. 107, 1945.

Type.—Rijksmuseum van Natuurlijke Histoire, Leiden, No. ???, obtained
by Ferdinand Deppe. The type locality was originally given as “Mexico”;
this was restricted to San Juan Teotihuacán, state of México, by Smith and
Taylor (1950: 334).

Diagnosis.—This subspecies is characterized by the presence of solid body-blotches
and lateral intercalary spots, dorsal interspaces less than five scales
in length, and the absence of paired stripes or rows of blotches, on the anterior
part of the body. There are 209 to 232 ventrals and 52 to 62 caudals. The
body-blotches number 27 to 49. In adults the anterior and posterior body-blotches
are black; the lateral intercalary spots are solid black. In many
individuals black dashes connect the adjacent corners of the dorsal body-blotches
(Pl. 45, Fig. 1). In juveniles the anterior, dorsal body-blotches are
black, whereas those at the midbody and posteriorly are brown.

Variation.—Geographically, scutellation varies only slightly. Comparison
of specimens from the northern part of the Mexican Plateau
(Chihuahua, Coahuila, and Durango—5 specimens), the central part
of the plateau (Aguascalientes, San Luis Potosí, and Zacatecas—13
specimens), the southern part of the plateau (Guanajuato, Jalisco,
México, and Michoacán—18 specimens), and Puebla and southern
Veracruz (12 specimens) shows the average number of ventrals for
these samples to be, respectively, 221.6, 216.7, 221.3, and 220.0. The
average number of dorsal body-blotches for the same samples are,
respectively, 36.6, 37.7, 38.4, and 34.6. Only in the southernmost
sample is there a noticeable difference in the number of blotches.

The specimen from Párajo Verde, Veracruz, was considered to
be an intergrade between P. deppei and P. lineaticollis by Smith
(1943: 461), who stated that, although the snake had 231 ventrals
and dark lateral streaks as does deppei, it had light-centered dorsal
blotches and stripes on the neck as does lineaticollis. This
specimen (USNM 110892) has a high number of ventrals for
deppei; one from Jalisco has 232, and one each from Guanajuato
and Veracruz have 229. The blotches posteriorly are lighter than
those anteriorly and are slightly lighter in the center than at the
periphery. Two anterior blotches are divided medially and narrowly
connected by black streaks. Although these are somewhat
suggestive of the pattern of lineaticollis, they are more nearly like
that of deppei. Four other specimens from the same area are
typically deppei. There is some doubt as to the actual provenance
of the snake stated to have come from Párajo Verde, for, according
to Smith (1943: 460), the snake had been tied to a truck and
dragged halfway down the slopes of the Cumbres de Acultzingo,
where he found it. He surmised that it probably was dragged
no farther than the settlement, Párajo Verde, at the Cumbres de
Acultzingo.

Fugler and Webb (1956: 171) commented on the uniformly
brown dorsum of a specimen (KU 39564) from 16 miles east and
18 miles north of Ocampo, Coahuila. It has a higher number of
ventrals (242) and caudals (88) than is known for deppei. It is,
without a doubt, a Pituophis. It is not Pituophis catenifer, as attested
to by the presence of only two prefrontals. The high number
of ventrals and caudals, together with the uniform dark brown
dorsum, provide a combination of characters indicating that this
specimen may represent an undescribed species in the deppei group
of Pituophis.

Distribution.—Southern Chihuahua and southern Coahuila southward on
the western and central parts of the Mexican Plateau to the Valley of México
and to southeastern Puebla and adjacent Veracruz.

Specimens examined.—Total of 63, as follows: Aguascalientes: 16 km.
N of Aguascalientes, UIMNH 27149; 17 km. E of Aguascalientes, UIMNH
36222; 5 km. SW of Aguascalientes, KU 29495; Cavillito, UIMNH 28134;
11 km. N of Rincon de Romos, UIMNH 40359-60; 2 km. N of San Francisco
de los Romos, UIMNH 27569. Chihuahua: USNM 8321 (2 specimens);
Semachique, CNHM 11825. Coahuila: Castanuelas, MCZ 407. Distrito
Federal: Lago Xochimilco, UIMNH 18709; Pedregal, UMMZ 99790. Durango:
Coyotes, CNHM 1497; Hacienda Magdalena, USNM 46365; Llano
Grande, UMMZ 113634. Guanajuato: USNM 16442; Acambaro, KU 45003;
Irapuato, UIMNH 35055. Jalisco: Atemajac, USNM 46385; Guadalajara,
USNM 24969; 5 km. SE of Guadalajara, KU 29508; Jamay, AMNH 19848-9,
19851-2; 3 km. WNW of Lagos de Moreno, KU 27727; 5 km. NW of Sayula,
UMMZ 101933. México: Atzocozlco, AMNH 19850; Chalco, USNM 110889;
San Juan Teotihuacán, EHT-HMS 5378, 5383, MCZ 16051. Michoacán: 6
km. E of Carapan, AMNH 69940; 3 km. W of Carapan, UMMZ 114598; 14
km. W of Morelia, UMMZ 104969; Tacambaro, USNM 46557; Tacícuaro,
USNM 110888; 11 km. W of Zacapu, UMMZ 104968. Puebla: Alseseca,
UIMNH 36221; Atlixco, USNM 46433; Puebla, AMNH 19856; 30 km. N
of Puebla, USNM 110887; Tecamachalco, UMMZ 88688; 16 km. SSE of
Tecamachalco, UMMZ 114597; Tehuacan, UMMZ 88687; 22 km. N of
Tehuacan, EHT-HMS 5377. San Luis Potosí: USNM 46554; 26 km. SW
of San Luis Potosí, UIMNH 28133. Veracruz: 3 km. W of Acultzingo, KU
23978; Cumbres de Acultzingo, UIMNH 36224, 36226, UMMZ 114596;
Párajo Verde, USNM 110892; questionably from Potrero Viejo, UMMZ
89358-9. Zacatecas: 16 km. E of Somberete, UIMNH 27147; 1 km. SW of
Tiburcio, KU 33599; 3 km. ESE of Troncoso, KU 29494; 10 km. W of Villa
de Arriaga (San Luis Potosí), UIMNH 27151; 24 km. NW of Zacatecas,
UIMNH 6393; 13 km. SE of Zacatecas, UIMNH 27148; 26 km. SE of
Zacatecas, UIMNH 27568.

Pituophis deppei jani Cope

Arizona jani Cope, Proc. Acad. Nat. Sci. Philadelphia, p. 369, 1860.

Pituophis deppei jani, Stull, Occas. Papers Mus. Zool. Univ. Michigan,
no. 250, p. 2, October 12, 1932, Bull. U. S. Natl. Mus., no. 175, p. 42,
April 23, 1940; Smith, Zool. Ser. Field Mus. Nat. Hist., vol. 29, p. 145,
February 29, 1944; Smith and Taylor, Bull. U. S. Natl. Mus., no. 187,
p. 107, 1940.

Type.—United States National Museum, No. 1522, from Buena Vista,
Coahuila, obtained by Lieutenant Darius N. Couch.

Diagnosis.—This subspecies is characterized by solid body-blotches that are
black anteriorly and brown posteriorly, anterior dorsal interspaces six or more
scales in length, and the absence of dark stripes or rows of spots on the anterior
part of the body. There are 215 to 235 ventrals, 52 to 68 caudals, and 21
to 31 dorsal body-blotches. The position of the lateral intercalary spots and
lateral streaks are the same as in deppei deppei.

Variation.—Throughout the range of this subspecies the posterior
body-blotches are brown and noticeably lighter than the anterior
ones. Juveniles are colored like adults. Specimens from the
northern part of the range (Nuevo León and Tamaulipas) have
21 to 28 (average 24.0) dorsal body-blotches and 7 to 11 (average
8.9) scales in the interspace between the first and second dorsal
body-blotches, as compared with specimens from the southern
part of the range (Hidalgo, Queretaro, and San Luis Potosí),
which have 24 to 31 (average 27.7) dorsal body-blotches and 6
to 10 (average 7.8) scales in the first interspace. Likewise, there
is a difference in the number of ventrals between the northern and
southern samples; those from the north have an average of 228.8
ventrals, and those from the south have 222.0. In all of these
characters the southern sample shows trends towards the southern
subspecies, deppei, which has fewer ventrals, fewer scales in
the first interspace, and more dorsal body-blotches.

Distribution.—Eastern part of the Mexican Plateau and lower leeward
slopes of the Sierra Madre Oriental from Hidalgo and Queretaro northward
to southeastern Coahuila.

Specimens examined.—Total of 28, as follows: Coahuila: Buena Vista,
USNM 1522; 50 km. W of La Rosa, EHT-HMS 5374. Hidalgo: Ixmiquilpan,
USNM 110890-1; 24 km. S of Ixmiquilpan, EHT-HMS 5373; Jacala,
UMMZ 80937; 35 km. E of Pachuca, UMMZ 99552; 16 km. E of Tulancingo,
KU 40357. Nuevo León: Ojo de Agua near Galeana, CNHM 33564-5.
Queretaro: Cadereyta, UMMZ 99791-3. San Luis Potosí: Charcas, UMMZ
77256-8; San Diego, UMMZ 77254-5; 24 km. NE of San Luis Potosí, UIMNH
18711; 30 km. NE of San Luis Potosí, UIMNH 27150, 28135. Tamaulipas:
Miquihuana, MCZ 19544-50.

Pituophis lineaticollis lineaticollis Cope, new combination

Arizona lineaticollis Cope, Proc. Acad. Nat. Sci. Philadelphia, p. 300, 1861.

Pituophis lineaticollis, Stull, Occas. Papers Mus. Zool. Univ. Michigan, no.
250, p. 2, October 12, 1932, Bull. U. S. Natl. Mus., no. 175, p. 47,
April 23, 1940.

Pituophis deppei lineaticollis, Smith, Proc. U. S. Natl. Mus., vol. 93, p. 460,
1943; Smith and Taylor, Bull. U. S. Natl. Mus., no. 187, p. 108, 1945.

Pituophis deppei brevilineata Schmidt and Shannon, Fieldiana-Zool., vol.
31, p. 79, February 20, 1947.

Type.—No type specimen is known. Cope (1861: 300 and 1887: 72)
stated that the specimen was from the southern Mexican Plateau and that it
was collected by Carlos Sartorius. Smith and Taylor (1945: 108 and 1950:
348) gave the type locality as Jalapa, Veracruz. Although this locality was
the source of many specimens sent to the United States by Sartorius, it is
not within the known range of lineaticollis, and therefore cannot appropriately
be thought of as the type locality. In the absence of a type specimen and a
justifiable type locality, I hereby designate as a neotype, University of Michigan
Museum of Zoology, No. 114668. This specimen was collected 24 kilometers
northwest of Ciudad Oaxaca, Oaxaca, on February 29, 1956, by William E.
Duellman. It is an adult female having 229 ventrals, 67 caudals, and long
black neck-stripes followed posteriorly by 23 light-centered dorsal body-blotches.

Diagnosis.—This subspecies is characterized by the presence of continuous
dark paravertebral stripes on the anterior part of the body, and light-centered
dorsal body-blotches and lateral intercalary spots (Pl. 45, Fig. 2). There are
229 to 258 ventrals, 54 to 72 caudals, and 23 to 45 dorsal body-blotches
posterior to the neck-stripes. The young are colored like the adults.

Variation.—Specimens from the southern part of the range in
Oaxaca have 229 to 245 ventrals (average 238.3); to the north on
the Mexican Plateau in the state of Michoacán seven specimens
have 231 to 243 (average 237.1) ventrals. In the relatively isolated
mountain ranges of the Sierra del Sur in Guerrero and the Sierra
de Coalcomán in southern Michoacán the ranges of variation and
average numbers of ventrals are, respectively, 234 to 258 (245.8)
and 236 to 246 (242.2). The longest neck-stripes are found in specimens
from Oaxaca and Guerrero; nevertheless, some specimens from
the Mexican Plateau in Michoacán and three of the four specimens
from the Sierra de Coalcomán have neck-stripes equally long. One
specimen from 40 kilometers north of Ciudad México and several
from the vicinity of Tancítaro, Michoacán, have rather shorter
neck-stripes. One specimen from Dos Aguas, Michoacán, has the
neck-stripes partially fragmented into rows of spots as in gibsoni.

On the basis of specimens from Tancítaro, Michoacán, Schmidt
and Shannon (1947: 79) described the subspecies brevilineata,
which they diagnosed as differing from lineaticollis in having fewer
ventrals and shorter neck-stripes. The present data suggest that
the characters used to diagnose the subspecies are variable not
only in Michoacán, but throughout the range of the species. Consequently,
Pituophis (deppei) brevilineata Schmidt and Shannon
(1947) is placed in the synonymy of Pituophis lineaticollis lineaticollis
Cope (1861).

Distribution.—The southern part of the Mexican Plateau in the states of
Michoacán, México, and Morelos, the Sierra de Coalcomán in southern
Michoacán, and the Sierra del Sur in Guerrero and Oaxaca.

Specimens examined.—Total of 25, as follows: Guerrero: Acahuizotla,
USNM 46537; Chilpancingo, CNHM 38356-9, UIMNH 35000, UMMZ
85724-5; Omiltemi, USNM 46462. México: 40 km. N of Ciudad México,
UIMNH 36223. Michoacán: Acuaro de las Lleguas, UMMZ 112565; Dos
Aguas, UMMZ 118786, 119567-8; 40 km. E of Morelia, UMMZ 101932;
Tancítaro, CNHM 37126, 39069-72. Morelos: 1 km. W of Tepoztlán,
UMMZ 101931; Tres Cumbres, UIMNH 35001. Oaxaca: 25 km. N of El
Soledad, UIMNH 6210; 24 km. NW of Oaxaca, UMMZ 114668; San Pedro
Quiechapa, USNM 110893.

Pituophis lineaticollis gibsoni Stuart, new combination

Pituophis deppei gibsoni Stuart, Proc. Biol. Soc. Washington, vol. 67, p.
172, August 5, 1954.

Type.—University of Michigan Museum of Zoology No. 107060, obtained
by Colvin Gibson. Type locality: Yepocapa, Chimaltenango, Guatemala.

Diagnosis.—This race is characterized by paired, elongated, pale-centered,
paravertebral spots on the anterior part of the body. Posterior to the paired
spots are 22 to 27 dorsal body-blotches; these and the lateral intercalary spots
have pale centers. There are 234 to 246 ventrals and 57 to 65 caudals.

Variation.—The few specimens that are available from a small
geographic area do not permit a discussion of geographic variation
at this time. All of the specimens have the paired paravertebral
spots and blotches with light centers. In this respect the population
of lineaticollis east of the Isthmus of Tehuantepec is noticeably
different from the nominal subspecies in the Mexican highlands.
Smith and Taylor (1945: 108) listed a specimen from San Cristobal,
Chiapas. I have not seen this specimen and so do not know to
which subspecies it belongs. On geographical grounds it probably
is gibsoni.

Distribution.—Guatemalan highlands and probably highlands of Chiapas.
Aside from the specimens examined, two others are known—one from Volcán
Agua, Sacatepequez (Slevin, 1939: 400), and one from Dueñas, Sacatepequez
(Boulenger, 1894: 65); these localities are not shown in figure 1.

Specimens examined.—Eight, as follows: Guatemala: Chimaltenango:
Chichavac, CNHM 1927; Finca El Tesoro, 3 km. SE of Acatenango, UMMZ
107062-3; Finca Recreo, 4.5 km. SW of Yepocapa, UMMZ 107381; Río Los
Positos, 5.5 km. NE of Yepocapa, UMMZ 107061; Río Sobolopop, 8 km. W
of Patzún, UMMZ 107064; Yepocapa, UMMZ 107060. El Quiche: Nebaj,
UMMZ 89202.

LITERATURE CITED

Boulenger, G. A.

1894. Catalogue of the snakes in the British Museum (Natural History). London, 2:xi + 382 pp., pls. 1-20.

Cope, E. D.

1860. Descriptions of reptiles from tropical America and Asia. Proc. Acad. Nat. Sci. Philadelphia, 1860:368-374.

1861. Contributions to the ophiology of Lower California, Mexico, and Central America. Proc. Acad. Nat. Sci. Philadelphia, 1861:292-306.

1887. Catalogue of the batrachians and reptiles of Central America and Mexico. Bull. U. S. Natl. Mus., 32: 1-98.

Duméril, A. M. C.

1853. Prodrome général de la classification des serpents. Mem. Acad. Sci. Inst. France, 23:399-536, 2 pls.

Duméril, A. M. C., and Bibron, G.

1854. Erpétologie générale, ou histoire naturelle des reptiles. Paris, 7 (pt. 1): xvi + 780 pp.

Fugler, C. M., and Webb, R. G.

1956. Distributional notes on some reptiles and amphibians from southern and central Coahuila. Herpetologica, 12:167-171.

Günther, A.

1885-1902. Biologia Centrali-Americana. Reptilia and Batrachia. London, xx + 326 pp., pls. 1-76.

Jan, G.

1863. Elenco sistematico degli ofidi. Milan, 143 pp.

Schmidt, K. P., and Shannon, F. A.

1947. Notes on amphibians and reptiles of Michoacan, Mexico. Fieldiana-Zool., 31 (9):63-85.

Slevin, J. R.

1939. Notes on a collection of reptiles and amphibians from Guatemala. I. Snakes. Proc. California Acad. Sci., 4th, ser., 23 (26):393-414, pls. 37-38.

Smith, H. M.

1943. Summary of the collections of snakes and crocodilians made in
Mexico under the Walter Rathbone Bacon Traveling Scholarship.
Proc. U. S. Natl. Mus., 93:393-504.

1944. Snakes of the Hoogstraal Expeditions to northern Mexico. Zool.
Ser. Field Mus. Nat. Hist., 29 (8):135-152.

Smith, H. M., and Taylor, E. H.

1945. An annotated checklist and key to the snakes of Mexico. Bull.
U. S. Natl. Mus., 187: iv + 239 pp.

1950. Type localities of Mexican reptiles and amphibians. Univ. Kansas
Sci. Bull., 33 (8):313-380.

Stuart, L. C.

1954. Descriptions of some new amphibians and reptiles from Guatemala.
Proc. Biol. Soc. Washington, 67:159-178.

Stull, O. G.

1932. An annotated list of the forms of the genus Pituophis. Occas.
Papers Mus. Zool. Univ. Michigan, 250:1-5.

1940. Variations and relationships in the snakes of the genus Pituophis.
Bull. U. S. Natl. Mus., 175:vi + 225 pp.

Transmitted February 2, 1960.

28-2493

Transcriber’s Notes

“Rijkmuseum van Natuurlijke Histoire” changed to “Rijksmuseum van Natuurlijke Historie” (Rijksmuseum van Natuurlijke Historie, Leiden)

Period changed to comma (Erpétologie générale, vol. 7, p. 268)

“Chipas” changed to “Chiapas” (Guatemalan highlands and probably highlands of Chiapas.)

The style of the majority of citations in this paper are of the form “(year: page)”. A small number of citations been ammended to include the space following the colon.