Specimens from the Sierra de Coalcomán are noticeably different from those inhabiting the mountains rising from the Mexican Plateau. Of 45 specimens from Cerro Tancítaro and adjacent areas on the Mexican Plateau and in the Cordillera Volcánica, 15 have twelve longitudinal rows of dorsal scales and 30 have fourteen rows. Of seven specimens from the state of México, 5 have twelve rows and 2 have fourteen; of nine specimens from central Veracruz, 8 have twelve rows and one has fourteen; of six specimens from Hidalgo, 5 have twelve rows and one has sixteen; of two specimens from Guanajuata, one has fourteen and the other has sixteen rows. All of the 35 specimens from the Sierra de Coalcomán have sixteen rows. Furthermore, these specimens have the superciliary row extended anteriorly, so that the anterior superciliary is in broad contact with the loreal. Specimens from Cerro Tancítaro have a shorter superciliary row, so that the anterior superciliary is not in broad contact with the loreal. These characters were used by Tihen (1949:220) to distinguish Gerrhonotus imbricatus ciliaris from G. imbricatus imbricatus. According to Tihen, the subspecies G. imbricatus ciliaris ranges from Guanajuato and Hidalgo northward to Chihuahua and Coahuila, whereas the nominal subspecies occurs from Michoacán and Hidalgo southward to Oaxaca. Specimens from the Sierra de Autlán in Jalisco are like those from Cerro Tancítaro; consequently, there seems to be no connection between the populations of G. imbricatus ciliaris in the mountains of the northern part of the Mexican Plateau with the ciliaris-like individuals found in the Sierra de Coalcomán. The acquisition and study of additional material from throughout the range of the species is necessary to clarify the picture of geographic variation. Until then, I prefer to consider all of the specimens from Michoacán as Gerrhonotus imbricatus imbricatus.

The largest specimen is a male having a snout-vent length of 136 mm. Two juveniles collected in July 24, 1960, have snout-vent lengths of 36 and 42 mm. A specimen having a snout-vent length of 127 mm. and a tail length of 145 mm. was regurgitated by a Crotalus pusillus, which had a body length of 550 mm.

Gerrhonotus imbricatus imbricatus is an inhabitant of coniferous forests. In the Cordillera Volcánica it occurs from 1500 to 3500 meters at the top of Cerro Tancítaro. In the Sierra de Coalcomán it occurs from 2100 to 2700 meters. On July 4, 1955, a pair was found in copulation beneath a pine log at 2700 meters on Cerro Barolosa. The male was lying on top of the female and was holding her head firmly in his jaws; the male's tail was curled under the female's tail, so that the cloacae were in contact.

Serpentes

Typhlops braminus (Daudin)

Both specimens known from Michoacán were collected by Gadow in 1908. Peters (1954:20) remarked that the specimen from Arteaga probably does not indicate a rapid spreading of the species, which most likely was introduced into México at the time that vessels were stopping at Acapulco from the Philippines (Taylor, 1940b:444), but instead may indicate that pack trains from Acapulco passed through the Sierra de Coalcomán. The occurrence of this snake along a long-used camino substantiates this belief.

Leptotyphlops bressoni Taylor

This species still is known definitely only from the type specimen collected on the lower slopes of the Cordillera Volcánica at the northern edge of the Tepalcatepec Valley. A specimen (now lost) reported from Aguililla by Cope (1887:63) possibly represents this species (see Smith and Taylor, 1945:21, and Peters, 1954:20).

Leptotyphlops gadowi Duellman

No additional specimens of this species have been collected since the species was described by Duellman (1956b:93). Data given with the specimen by Gadow indicate that it came from his camp above Apatzingán at an elevation of about 800 meters. Although the exact position of this camp is unknown, the lower slopes of the Cordillera Volcánica above Apatzingán usually support arid scrub forest at elevations below 1000 meters. Therefore, this species probably is an inhabitant of the arid scrub forest.

Leptotyphlops phenops bakewelli Oliver

The five specimens from the coastal lowlands are from elevations of less than 150 meters; these were collected by Peters (1954:20); the specimen from La Salada is from an elevation of 580 meters in the Tepalcatepec Valley. Peters (loc. cit.) remarked that the rostral and the tip of the tail that were described as white by Oliver (1937:17) actually are sulphur-yellow in life.

Loxocemus bicolor Cope

As noted by Peters (1954:21), this species was not recorded from Michoacán by Smith and Taylor (1945:27), but Gadow (1930:30) collected a specimen at La Orilla in 1908. This specimen (BMNH 1914.1.28.124) is a male having 235 ventrals and 47 caudals, a dark brown dorsum, and cream-colored labials and venter. The anterior chin-shields are considerably longer than the scales bordering the chin-shields. In these characters this specimen agrees with the diagnosis of Loxocemus bicolor given by Taylor (1940c:447), who revived Loxocemus sumichrasti Bocourt. Of the six specimens from Apatzingán in the Tepalcatepec Valley, three males have 243 to 253 (246.6) ventrals and 44 to 45 (44.3) caudals; three females have 238 to 247 (244.0) ventrals and 42 to 44 (43.0) caudals. Certain characters of scutellation utilized by Taylor for separating L. bicolor and L. sumichrasti are inconsistent in this series. The chin-shields are longer than the adjacent scales, like those illustrated in L. bicolor by Taylor (op. cit., fig. 1). The relative lengths of the prefrontal and internasal sutures are subequal, or the prefrontal suture is slightly longer. Thus, in these characters of scutellation these snakes are like L. bicolor, but in coloration they are like L. sumichrasti; the dorsal color in life was an iridescent dark bluish gray, and the belly was pale gray or bluish gray.

The supposed differences in scutellation between L. bicolor and L. sumichrasti have been questioned by Woodbury and Woodbury (1944:360); these authors treated L. sumichrasti as a subspecies of L. bicolor. As pointed out by Zweifel (1959b:5), such an arrangement is not tenable, for, although individuals with each kind of color pattern have not been collected together at any one locality, the over-all geographic picture is one of sympatric distribution. Only snakes having the coloration of L. sumichrasti have been collected in the Balsas-Tepalcatepec Basin. I agree with Zweifel (loc. cit.) that on the basis of morphological similarities and sympatric distribution, L. bicolor and L. sumichrasti seem to be dimorphic phases of the same species, showing no more striking differences in coloration than Lampropeltis getulus californiae, a now classical example of pattern dimorphism in snakes.

In Michoacán, as in other parts of its range, Loxocemus bicolor inhabits arid scrub forest environments at low elevations.

Boa constrictor imperator Daudin

These specimens have come from a variety of habitats from elevations of less than 1,000 meters. The species seems to be equally abundant in the broad-leafed semi-deciduous forests of the coastal foothills and in the arid Tepalcatepec Valley. In the latter area most of the specimens were collected at night.

Coniophanes fissidens dispersus Smith

Further collecting in southern Michoacán has failed to add additional material of this species, which is known in the state from the one specimen collected by Gadow in 1908. The species possibly ranges throughout the coastal foothills of the Sierra de Coalcomán. Peters (1954:21) described the specimen from Arteaga.

Coniophanes lateritius lateritius Cope

The one specimen available from Michoacán of this apparently rare species was discussed by Wellman (1959:127), who pointed out that although the specimen was geographically intermediate between the subspecies C. l. lateritius (Jalisco and Nayarit) and C. l. melanocephalus (Morelos and Puebla), the specimen (UMMZ 118954) was like C. l. lateritius in scutellation and in color pattern differed from other known specimens of the species in having had in life a pale orange, instead of a brick-red, dorsum. Additional specimens from the Sierra de Coalcomán will be required in order to determine whether this specimen is a representative of an orange-colored population or merely is aberrant in coloration.

The present specimen is from an elevation of 900 meters in oak forest on the southern slopes of the Sierra de Coalcomán; other locality records for the species indicate that it inhabits broad-leafed forest in foothills from Nayarit to Puebla.

Conophis vittatus vittatus Peters

All specimens of this terrestrial snake have been collected in areas of scrub forest between 800 and 1100 meters above sea level. Since the species is known from the coastal regions of Guerrero and Colima, its absence from the cost of Michoacán is unexplainable; probably the lack of specimens from these areas is due solely to inadequate collecting.

Conopsis biserialis Taylor and Smith

This species is abundant in the coniferous forests at elevations from 1550 to 2800 meters throughout the Cordillera Volcánica; apparently it does not occur in the Sierra de Coalcomán.

On August 1, 1956, a copulating pair was found beneath a rock at Capácuaro.

One of the best characters to distinguish this species from Toluca lineata, which occurs with Conopsis throughout its range in Michoacán, is the presence of large, black ventral blotches in Conopsis biserialis, as contrasted with the two rows of small black spots in Toluca lineata.

Conopsis nasus Günther

This species has been collected in oak, pine-oak, and fir forests at elevations of 1900 to 2450 meters on the mountains rising from the Mexican Plateau. It does not seem to be so abundant as Conopsis biserialis. Sufficient ecological data to determine differences in habitat between the two species have not been compiled.

Diadophis dugesi Villada

Apparently this snake is uncommon in Michoacán. It has been found only at elevations of 1900 to 2200 meters in pine and pine-oak forests on the mountains rising from the Mexican Plateau.

Dryadophis melanolomus stuarti Smith

The few specimens indicate that in Michoacán, as elsewhere on the Pacific coast of México, this species is restricted to forested regions on the coastal plain. It does not occur in the Tepalcatepec Valley.

The coloration, in life, of a juvenile (UMMZ 114604) is as follows: The dorsum is uniform pale grayish tan on posterior one-third of body and on tail; anteriorly there are pale grayish tan middorsal blotches separated by grayish white interspaces, which are about one-half the length of the blotches. Posteriorly the blotches are less distinct, fading into the uniform grayish tan ground color of the posterior part of the body. The blotches extend laterally onto the fourth and fifth scale rows. Large squarish lateral intercalary blotches of darker brown interconnect with the dorsal blotches. The top of the head is pale olive-brown; a dark brown postorbital stripe extends from the eye to the posterior edge of the last upper labial. The labials, chin, and ventrals 1-30 are creamy white, changing to a dusty cream-color posteriorly; the chin and ventrals 1-30 are heavily spotted with dark brown. The iris is a cream-color above and chocolate brown below; the tongue is blue.

Drymarchon corais rubidus Smith

Not all of the specimens from Michoacán are typical in color pattern of this subspecies, as defined by Smith (1941a:475). All specimens from the Tepalcatepec Valley are uniformly black above; they have reddish or cream-colored chins and the anterior two-thirds of the belly salmon-pink or reddish buff. Individuals from the Sierra de Coalcomán (Arteaga and Arroyo El Salto) are like those from the Tepalcatepec Valley. Three specimens from the coastal lowlands differ noticeably in color pattern:

UMMZ 104504, adult male (Ostula).—Pale brown above flecked with black anteriorly; at midbody, flecks form narrow transverse bands that become progressively wider posteriorly, until on tail no brown pigment evident, all ventrals reddish buff, except last eight, which are black.

UMMZ 104602, adult female (La Placita).—Black above, reddish cross-bands and flecks on all of body; dorsal and ventral surfaces of tail black; chin cream-color and entire belly reddish buff.

UMMZ 114626, adult male (San Juan de Lima).—Black above; dull rust-colored cross-bands on anterior half of body; chin white; belly rust-colored on anterior two-thirds of body and black posteriorly.

One specimen from La Palma on the Mexican Plateau (KU 29275) has the top of the head an olive-color, the entire dorsum black, the chin and ventrals 1-42 a cream-color, remainder of venter black, and all of the labials heavily barred with black. A juvenile from Capirio in the Tepalcatepec Valley (UMMZ 114627) is black above and has pale olive-colored flecks on the anterior one-third of the body; the top of the head is dark olive-brown, and the sides of the head are somewhat paler. Anteriorly the belly is a cream-color; posteriorly it is black.

The specimens from the Tepalcatepec Valley are typical of Drymarchon corais rubidus. Those from the coastal lowlands differ in having large areas of brown or red pigment on the dorsum, a condition not mentioned by Smith in his description of the subspecies. The specimen from La Palma, like many others from various localities on the Mexican Plateau, resembles in certain characters D. corais orizabensis (Smith, op. cit.: 477). Our knowledge of the geographical variation in coloration in this species is incomplete; many populations have been assigned to subspecific rank without justification.

In Michoacán this species is found from sea level to 1350 meters in the Sierra de Coalcomán and to 1300 meters at La Palma on Lago de Chapala. It has been collected in scrub forest, semi-deciduous broad-leafed forest, and oak forest.

Drymobius margaritiferus fistulosus Smith

This snake is abundant in the lowlands of the state; the few specimens listed above are indicative not of the rarity, but rather of the speed and agility, of this diurnal snake. It most frequently is found near water, where there is a dense growth of vegetation. One individual was observed in a large pool inhabited by several small Rana pipiens, and another was seen along the bank of a hyacinth-choked river channel. A third individual was captured while it was in pursuit of a Cnemidophorus.

This species has been collected on the coastal lowlands and seaward foothills of the Sierra de Coalcomán and in the Tepalcatepec Valley to elevations of 1150 meters.

Elaphe triaspis intermedia (Boettger)

Dowling (1960) has shown that specimens from the Balsas-Tepalcatepec Basin have fewer ventrals and caudals than those from the Sierra del Sur or the coast. All specimens from Michoacán were collected in open forest, either scrub or oak forest. They were found in drier situations than those described for the species in southern Tamaulipas by Martin (1958:69). In Michoacán Elaphe triaspis intermedia is known from the Tepalcatepec Valley, the lower slopes of the Cordillera Volcánica, and the western edge of the Mexican Plateau at an elevation of 1350 meters. It probably occurs in the lower parts of the Sierra de Coalcomán and along the Pacific coast, for it is known from the coastal lowlands of Guerrero and Colima. In August, 1951, I saw a snake that probably was this species in Barranca de Bejuco.

Enulius unicolor (Fischer)

This small snake has been collected from beneath rocks in brushy areas and broad-leafed forest between 900 and 1800 meters; it has not been found in coniferous forest. The limited ecological data suggest that the species inhabits the transition zone between the tropical scrub forest and the temperate hardwood forest.

All of the specimens have 17 rows of scales; four males have 169-178 (174.2) ventrals and 102-111 (106.8) caudals; two females have 192 and 195 ventrals and 96 and 87 caudals. Three individuals have one postocular on one side and two on the other; in the other specimens there are two postoculars on each side. The largest male has a body length of 232 mm. and a tail length of 130 mm.; the largest female has a body length of 274 mm. and a tail length of 119 mm.

Geagras redimitus Cope

Previously this species was known definitely only from the Plains of Tehuantepec, Oaxaca. Sphenocalamus lineolatus was described by Fischer (1883:5) from Mazatlán; this name has been placed in the synonymy of Geagras redimitus Cope. Although Fischer gave the type locality only as "Mazatlán" and did not designate the state, it is probable that the type originated from Mazatlán, Sinaloa. The present specimens are from a locality almost midway between Tehuantepec and Mazatlán and support the possibility that Geagras ranges along the Pacific coast of México from Oaxaca to Sinaloa.

The two specimens from Michoacán (UMMZ 114446-7), both males, have 118 and 122 ventrals, 31 and 33 caudals, body lengths of 108 and 81 mm., and tail lengths of 20 and 15 mm. Both have 1-1 preoculars, 1-1 postoculars, 1-2 temporals, 6-6 upper labials, and 5-5 lower labials. In life, the dorsum was pale tan; the top of the head and the middorsal and lateral stripes were dark brown; the belly was white. The occipital spots were pale pinkish tan. Both specimens were found beneath rocks in tropical semi-deciduous forest at an elevation of 15 meters on the coastal plain.

Geophis dugesi Bocourt

Aside from the three specimens listed above, there are two (SU 4407-8) bearing the data "Michoacán." Bocourt (1883:574) stated that the type specimen from Tangancícuaro had six or seven pale cross-bands on the anterior part of the body. An illustration, presumably of the same specimen, by Dugès (1884:Pl. 9) shows five distinct and one indistinct cross-bands. Of the four specimens that I have examined, none has more than three pale cross-bands, and one has only one indistinct cross-band. Two females have 154 and 158 ventrals and 38 and 37 caudals; two males have 150 and 151 ventrals and 43 and 42 caudals.

This species is known only from elevations between 1750 and 2050 meters on the southwestern edge of the Mexican Plateau in the state of Michoacán.

Geophis incomptus Duellman

This species, which seems to be related to Geophis maculiferus, is known only from the pine-oak forest in the vicinity of Dos Aguas (elevation 2100 meters) in the Sierra de Coalcomán. Aside from the five specimens comprising the type series, there are ten other specimens in the Museum of Zoology at the University of Michigan collected by Floyd L. Downs in July, 1960. Data from these specimens and those comprising the type series show that in this sample seven males have 146-153 (149.3) ventrals and 35-37 (36.0) caudals; eight females have 150-154 (152.4) ventrals and 29-34 (32.5) caudals. The largest specimen is a female with a body length of 344 mm. and a tail length of 53 mm.

Geophis maculiferus Taylor

The type and only known specimen of Geophis maculiferus (UIMNH 25078) is a female having 140 ventrals and 30 caudals, dorsal scales in 15 rows, one postocular, and an anterior temporal. Only one other species in México has dorsal scales in 15 rows and has an anterior temporal; that species is G. incomptus, which differs from G. maculiferus in having six or seven lower labials, instead of five, and in having the edges of the ventrals dark, instead of a uniformly cream-colored belly.

The locality from which the specimen was obtained lies at an elevation of 1630 meters on the southern slope of the Cordillera Volcánica. At that elevation there is an interdigitation of arid tropical scrub forest and pine-oak forest; probably Geophis maculiferus inhabits the pine-oak forest.

Geophis nigrocinctus Duellman

The three specimens comprising the type series of the species were found beneath logs and in a stump in pine-oak forest at an elevation of 2100 meters. A discussion of the variation in these specimens and of probable relationships of the species was given by Duellman (1959). Floyd Downs spent several days at Dos Aguas in July, 1960; although he found ten specimens of Geophis incomptus, no further specimens of G. nigrocinctus were obtained.

Geophis petersi Boulenger

This seems to be the most widespread species of Geophis in Michoacán. It has been found at elevations between 950 and 2350 meters, chiefly in pine or pine-oak forest. Boulenger (1894:321) described Geophis petersi from a specimen stated to be from Mexico City, a locality which probably is in error. The only localities from which the species is definitely known are those listed in this account.

Three males and five females from the Mexican Plateau and the Cordillera Volcánica have respectively 140-144 (141.7) and 143-151 (146.0) ventrals and 39-41 (40.0) and 29-35 (33.2) caudals. All have dorsal scales in 15 rows, 1 postocular, no anterior temporal, and a relatively small triangular supraocular. The specimen from Coalcomán (UMMZ 104698) was referred to Geophis nasalis by Peters (1954:22). This specimen is abnormal in several characters; in five places there is a fusion and separation of the vertebral and paravertebral scale rows, producing a change from 17 to 15 rows of dorsal scales. Fusion of the three rows takes place at the level of the 8th, 41st, 47th, 54th, and 65th ventrals. Furthermore, there is a small secondary postocular on each side of the head. In other characters the specimen is like G. petersi; the resemblances to that species are greater than to G. nasalis, which has been recorded from Guatemala and southern Chiapas.

Geophis tarascae Hartweg

A female of this species was collected in the Parque Nacional at the north edge of Uruapan in 1899, and a male was taken there in 1947; these specimens were used by Hartweg in his description of the species. Floyd L. Downs obtained another specimen in the Parque Nacional on July 19, 1960. It has 164 ventrals and 46 caudals; in life, the ground color of the neck was brown with a purplish tint; the dorsal markings were black; the chin was a cream-color, and the belly was white. This specimen is distinguished from those of all other species of Geophis in Michoacán in that it has dark irregular cross-bars on the dorsum and a row of dark spots on the venter.

Hypsiglena torquata ochrorhyncha Cope

The systematic status of the geographic variants of Hypsiglena in México and southwestern United States has been commented on by several authors. Tanner (1944) considered H. torquata and H. ochrorhyncha to be distinct species; Bogert and Oliver (1945:379) and Duellman (1957b:238) presented evidence indicating that H. torquata and H. ochrorhyncha intergrade in Sinaloa and southern Sonora. In Hypsiglena the scutellation, including the numbers of labials, dorsals, ventrals, and caudals, seem to vary in a clinal manner. Nevertheless, these snakes can be divided into two distinct populations on the basis of the nuchal color pattern, consisting of an ochrorhyncha-type (a broad dark nape-band, the lateral edges of which extend anteriorly and fuse with a postorbital stripe, and a narrow nape stripe extending from the posteromedian edges of the parietals to the dark nape band) and a torquata-type (a somewhat narrower dark nape-band bordered anteriorly by a pale nuchal area, and no dark nape stripe). Snakes having the ochrorhyncha-type of nuchal pattern are found on the Mexican Plateau from Michoacán northward into the desert regions of Sonora and the southwestern United States. Snakes having the torquata-type of pattern are found on the coastal lowlands and adjacent slopes of the Sierra Madre Occidental from southern Sinaloa to Colima and thence inland in the Balsas-Tepalcatepec Basin to Morelos and Guerrero. An exception is Hypsiglena torquata dunklei from Forlón and San Fernando, Tamaulipas; it has the torquata-type of nuchal pattern. The distributional picture is somewhat complicated because some individuals having the torquata-type of nuchal pattern also have a faint nape stripe. If these are taken as exceptions, the general picture of distribution in México is H. t. torquata on the Pacific lowlands from Sinaloa southward to the Balsas Basin and H. t. ochrorhyncha on the Mexican Plateau.

Smith (1943:433) resurrected Hypsiglena jani Dugès for the snakes of the ochrorhyncha-type on the southern part of the Mexican Plateau. He stated that the southern specimens differed from northern ones in having a nuchal spot 9 or 10 scales in length, as compared with a spot 2 to 6 scales in length in northern specimens. A cursory examination of specimens from the areas between Arizona and Michoacán showed that there is a gradual increase in the size of the spot from north to south. If no other characters can be found to distinguish the populations, they should be considered as a single subspecies.

Hypsiglena affinis differs from H. torquata in possessing 19 instead of 21 rows of dorsal scales. Additional material is needed from the western slopes of Jalisco and the Barrancas in Zacatecas and Durango, before definite allocation of affinis can be made.

Bogert and Oliver (1945:379) discussed the status of certain named populations in Baja California and concluded that only one species occurs there, and that the species probably is conspecific with H. torquata. A careful review of the genus Hypsiglena might show that there is only one species.

The one specimen from Michoacán (USNM 46513) is from an elevation of about 2300 meters near the southern edge of the Mexican Plateau.

Hypsiglena torquata torquata (Günther)

Specimens from the three mentioned localities have the dark nuchal spot bordered anteriorly by a pale blotch. In life the specimen from Capirio (UMMZ 114424) had rich reddish brown dorsal spots; the dorsal ground color was grayish white above and somewhat more gray laterally. The pale nuchal area was a cream-color, and the iris was grayish red.

All of the specimens were found in the arid scrub forest in the Tepalcatepec Valley at elevations between 200 and 350 meters.

Imantodes gemmistratus gracillimus (Günther)

The specimen from La Orilla was reported by Peters (1954:23) as Imantodes gemmistratus oliveri; Zweifel (1959c) showed that I. g. oliveri did not range west of Tehuantepec and that the snakes inhabiting the coastal lowlands of Guerrero, Michoacán, and Colima were assignable to the subspecies gracillimus. It may be assumed that this subspecies ranges throughout the coastal lowlands and foothills of the Sierra de Coalcomán.

Imantodes gemmistratus latistratus (Cope)

The one specimen from Michoacán was collected near the upper limits of the scrub forest on the slopes of the Cordillera Volcánica. Zweifel (1959c:10) stated that in certain aspects of coloration this specimen was like I. gemmistratus gracillimus, but in scutellation and other features of coloration it was like I. g. latistratus. There are too few specimens of this species to define the ranges of the various subspecies with any degree of accuracy, but from the limited number of specimens available, it seems that I. gemmistratus gracillimus occurs on the Pacific lowlands from Guerrero northward to Colima. Northward on the Pacific lowlands from Colima to Sinaloa and in the Balsas-Tepalcatepec Basin is found I. gemmistratus latistratus.

Lampropeltis doliata (Linnaeus)

The few specimens of this species from Michoacán show a wide range of variation; furthermore, the present systematic status of the subspecies of Lampropeltis doliata portrays an incongruous pattern of distribution. Specimens from the Sierra de Coalcomán have relatively narrow red bands that are not interrupted dorsally by extensions of the black rings; the scales in the red bands have black tips. The specimen from El Sabino (EHT-HMS 5253) and the one from the Río Nexpa on the coast (USNM 31491) have broader red bands; the scales in the red bands do not have black tips. A specimen from 24 kilometers west of Morelia (UIMNH 17782) and one from Uruapan (UMMZ 121508) have the red bands interrupted dorsally by extensions from the black rings.

Specimens from the Sierra de Coalcomán were referred to L. doliata blanchardi by Peters (1954:24), who noted that in some characters these snakes were like L. d. nelsoni and in others like L. d. polyzona. The individual from El Sabino was referred to L. d. nelsoni by Taylor (1940c:465); the one from 24 kilometers west of Morelia was referred to L. d. arcifera by Smith (1942c:198). If these assignments are correct, three subspecies of Lampropeltis doliata occur in Michoacán: blanchardi in the Sierra de Coalcomán, nelsoni on the coast and in the Tepalcatepec Valley, and arcifera on the Mexican Plateau and in the Cordillera Volcánica. Such a distribution is plausible, but the few specimens and our general lack of knowledge of the variation and relationships of the different populations do not permit a definite assignment at this time.

Lampropeltis ruthveni Blanchard

At the present time this species is known definitely from only three localities on the Mexican Plateau in Michoacán. An incomplete skin from El Sabino (EHT-HMS 5438) was referred to this species by Taylor (1940c:465); the specimen cannot be found, so verification of the identification cannot be made at this time.

Leptodeira latifasciata (Günther)

This nocturnal snake apparently ranges throughout the arid Balsas-Tepalcatepec Valley to elevations of about 1050 meters. It has been collected only in the arid scrub forest. Aside from the specimens listed by Duellman (1958a:93), there is one (UMMZ 120223) having eight body blotches, a body length of 510 mm. and a tail length of 103 mm.

Leptodeira maculata (Hallowell)

This snake is abundant in the arid Tepalcatepec Valley; most of the specimens have been collected in arid scrub forest at elevations of less than 500 meters. With the onset of the rains in late June and early July, large numbers of these snakes can be found around temporary pools, where they feed on small frogs and toads. In the dry season few individuals were found, and all of those were beneath cover. Specimens from the coast have more body-blotches than do those from the Tepalcatepec Valley (Duellman, 1958a:56); otherwise the snakes show little variation.

Leptodeira splendida bressoni Taylor

The range of Leptodeira splendida bressoni apparently does not overlap that of Leptodeira maculata; the latter is restricted to the lower reaches of the arid scrub forest, whereas L. s. bressoni inhabits the upper limits of the arid scrub forest and the lower part of the pine-oak forest. Specimens have been collected between 950 and 1630 meters on the slopes of the Cordillera Volcánica and at 950 meters in the Sierra de Coalcomán. At Uruapan individuals were found beneath rocks along a stream and in a stone fence. Leptodeira duellmani, which was described from Coalcomán by Peters (1954:25), is an aberrant individual of L. s. bressoni (Duellman, 1958a:56).

Leptophis diplotropis (Günther)

Most specimens of this species have been collected in tropical semi-deciduous forest at elevations of less than 1000 meters. In the Sierra de Coalcomán one was taken in pine-oak forest at an elevation of 1700 meters near Ocorla; another was found in broad-leafed forest between Aguililla and Dos Aguas at an elevation of 1600 meters. Most individuals have been seen in trees or bushes. The absence of broad-leafed forest in the Tepalcatepec Valley probably accounts for the absence of this snake in that area.

Manolepis putnami (Jan)