52 BULLETIN 17 5, UNITED STATES NATIONAL MUSEUM 



Omiltema, both in Guerrero, Mexico. P. lineaticollis has been 

 reported by Boulenger (1894, vol. 2, p. 65) and Gunther (1894, 

 p. 124) from as far south as Duenas, Guatemala, which is the southern- 

 most locality known for the form. I have not been able to find this 

 locality or Omiltema upon any map of the region. Cope (1887, p. 72, 

 and 1900, p. 861) and Gunther (1894, p. 124) give the locality "south- 

 ern Mexican plateau." Cope (1900, p. 861) says: "This species was 

 originally described from a specimen in the Museum of the Phila- 

 delphia Academy from Jalapa." This reference is confusing rather 

 than helpful, as there are four towns by that name in as many differ- 

 ent states of Mexico. It seems probable, however, that the town 

 referred to is Jalapa, Oaxaca, since it is in a direct line between 

 Guerrero and Guatemala, and thus undoubtedly lies within the 

 known range of the species. (Fig. 18.) 



Habits and habitat. — Apparently nothing has been recorded of the 

 habits of this species. 



Affinities. — That lineaticollis is closely related to the two subspecies 

 of deppei is clearly indicated by their common possession of two rather 

 than four prefrontals and the entrance into the orbit of two supra- 

 labials rather than one in all three forms, in contradistinction to all 

 the other members of the genus. The derivation of lineaticollis from 

 deppei is suggested by the ranges of these two forms (fig. 18), which 

 overlap in southern Mexico, while those of lineaticollis and jani, as 

 judged from our limited knowledge of each, are widely separated, with 

 that of deppei intermediate. The common tendency in both jani and 

 lineaticollis to a decrease in tail length and an increase in the numbers 

 of ventrals and caudals, as well as the tendency toward the develop- 

 ment of stripes (which results in marked continuous stripes in all 

 specimens of lineaticollis and in the formation of small discontinuous 

 stripes between the anterior spots in some specimens of jani), seems 

 to signify a common ancestry rather than a direct relationship. Cer- 

 tain tendencies probably appeared on the periphery of the ancestral 

 form, deppei, which became so accentuated as to give rise to a distinct 

 species in the case of lineaticollis, whereas they appeared to a much 

 lesser extent in each case in jani. 



The probable relationships of these forms have been expressed in 

 the diagram on page 42. 



Table 4 lists the specimens of this species examined. 



PITUOPHIS MELANOLEUCUS MELANOLEUCUS (Daudin) 



Coluber melanoleucus Datjdin, Histoire naturelle gen^rale . . . des reptiles, vol. 

 6, p. 409, 1803 (no type known; type locality, Florida and South Carolina). — 

 Harlan, Journ. Acad. Nat. Sci. Pliiladelphia, vol. 5, pt. 2, p. 359, 1827; 

 Medical and physical researches, p. 122, 1835. — Boulenger, Catalogue of 

 snakes in the British Museum, vol. 2, p. 68, 1894 (part). 



Pituophis melanoleucus Holbrook, North American herpetology, vol. 4, p. 7, 

 pi. 1, 1842. — Baird and Girard, Catalogue of North American reptiles, 



