470 PROCEEDINGS OF THE NATIONAL MUSEUM vol.93 



Male, ventrals 183 ; caudals 127 ; supralabials 9-9 ; infralabials 11-11 ; 

 preoculars 1-1, postoculars 2-2; temporals 2-1-2, 2-2 ; 4th, 5th, and 6th 

 supralabials enter orbit. 



The Museum has 14 other specimens, from the states of Colima 

 (Colima, Nos. 31618-9, 31621-2, 61966-9; Manzanillo, Nos. 31620, 

 46607, 61970), Guerrero (Acapulco, No. 46341), Guanajuato (Tupa- 

 taro, No. 10230), and Michoacan (Huetamo, No. 31077). 



♦SIBON BREVIFACIES (Cope) 



Two specimens are in the Museum, one the type (No. 24886) T8 and 

 another (No. 6562) from the same locality, Yucatan. 



SIBON DIMIDIATUS (Giinther) 



Five specimens (Nos. 109903-6, HMS No. 7311) were secured at 

 Piedras Negras, Guatemala. They were most frequently found under 

 loose bark of fallen trees. One is in too poor condition for scale counts 

 to be made. 



The supralabials are 8-9 in one, 8-8 in the others ; infralabials 9-9 in 

 one, 9-10 in two, 10-11 in one ; preoculars none in two, 1-1 in one (loreal 

 split vertically), 2-2 in one (loreal split, and in addition a small scale 

 split off lower corner of prefrontal) ; prefrontal entering orbit in all; 

 temporals 1-2 ; dark body bands 24 to 31, tail bands 17 to 19. 



The young are considerably different in coloration from the adults. 

 The young were described in the field as follows : All light areas of head 

 dark orange (burnt sienna) ; lower sides of head white, dorsal areas of 

 light body bands dark orange; these areas not so broad anteriorly 

 (2 scales) , broader posteriorly (5 to 7 scales) ; sides of light bands, belly 

 and tail pure white. In the single adult specimen the dark bands are 

 light brown, with a black border; the light bands are heavily stippled 

 with black on the 11 median scale rows, nearly white on the two outer 

 rows. The belly is also stippled somewhat. The Museum has no 

 others of the species. 



Ventrals and caudals, respectively, in No. 7311, 191, 122; No. 109903, 

 189, 111 ; No. 109905, 200, 124; No. 109906, 194, 126. 



♦SIBON NEBULATUS (Linnaeus) 



A single specimen (No. 7100) in the Museum is from Tierra Caliente, 

 Mexico. 



•SIBON SANNIOLUS (Cope) 



Three specimens are in the Museum, Nos. 6564 (type) 79 and 24888 

 from "Yucatan," and No. 46568 from Chichen Itza, Yucatan. 



78 Cope, 1866, p. 127. 

 " Cope, 1867b, p. 318. 



