Occasional Papers of the Museum of Zoology 7 



Range: The southern tliird of Arizona (except the portion 

 south and east of Tucson), extreme southeastern Cahfornia. 

 and the desert region about the head of the Gulf of Cahfornia. 



Type Specimen : U. S. National Museum No. 61318, male; 

 2/ miles west of Indian Oasis, Pima County, Arizona ; col- 

 lected by A. B. Howell July 7, 1918. 



Description of Type Specimen: In general with the char- 

 acteristics of T. getuhis boylii. Ventral plates, 230, plus one en- 

 tire anal; subcaudals, 52 pairs; 7 upper and 9 lower labials 

 on each side; one pre- and 2 post-oculars on each side, of the 

 latter the more ventral is the smaller; temporals, on each side, 

 two in the first row and three in the second. Loreal a little 

 longer than high, the upper posterior angle broadly obtuse, the 

 lower acute. Posterior chin shields a little more than half the 

 length and width of the anterior, and separated from each 

 other by two smaller scales. Other cephalic shields normal. 

 Scale rows anteriorly 23 (one less on the left side between the 

 24th and 34th ventrals and on the right between the 21st and 

 26th), changing, at about the level of the 146th ventral on the 

 left side and the 140th on the right, to 21, and, at the level of 

 the 182nd ventral, to 19, the formula being thus 23-21-23-21 -19. 



Total length 1060 mm. ; tail length 134 mm. ; tail length divid- 

 ed by total length .127. 



General color (hardened in formalin and preserved in al- 

 cohol) black or very dark brown. From head to tip of tail the 

 body is crossed by 37 white annuli, the scales of which are 

 white with dark brown at the bases. Three scales close behind 

 the parietals have each a white dot. The first complete ring is 

 about twelve scales behind the parietals. The four or five suc- 

 ceeding rings are split on the middorsal line and alternated. 

 The annuli are from one-half to one scale wide on the mid- 

 dorsal line, increasing to about three or four scales wide on the 



