82. UEOTHECA. 183 



Liophis tricinctus, Jan, Arch. Zool. Anat. Phus. ii. 1863, p. 301, and 



Icon. G4n. 18, pi. iv. fins. 4-6 (1866). 

 Pliocercus dimidiatus. Cope, Proc. Ac. Philad. 1865, p. 190, and 



Journ. Ac. Philad. viii. 1876, p. 138, and Proc. Amer. Philos. Sac. 



xxn. 1885, p. 183. 



sargii, Msch. Arch./. Nat. 1881, p. 225, pi. xi. figs. 1-3. 



Liophis elapoides, Garm. JV. Am. Pent. p. 69 (1883) ; Bocourt, Miss. 



Sc. Mex._, Rept. p. 635, pi. xli. fig. 6 (1886). 

 — — elapoides, vars. diastema et ssqualis, Bocourt, I. c. figs. 7 & 8. 

 Elapoohrus sequalis, GUnth. Biol. C.-Am., Rept. p. 106, pi. xxxvi. 



fig. A (1893). '^ ^ ' ^ 

 dimidiatus, GUnth. I. c. p. 107. 



Eye rather small ; snout short, rouhded. Rostral nearly twice 

 as broad as deep, just visible from above ; internasals shorter than 

 the prasfrontals ; frontal as long as or a little longer than its 

 distance from the end of the snout, shorter than the parietals ; 

 loreal as long as deep ; one or two prasoculars and a small subocular ; 

 two postoculars ; temporals 1 + 1 (rarely 1 + 2) ; eight (rarely nine) 

 upper labials, fourth and fifth (or fifth and sixth) entering the eye ; 

 five lower labials in contact with the anterior ohin-shields, which 

 are a little longer than the posterior. Scales in 17 rows. Ventrals 

 124-143 ; anal divided ; subcaudals 85-127. Eed above, the scales 

 usually tipped with black, with single or triple black annuli, the 

 annuli when triad separated by yellow interspaces ; some large black 

 spots may be present on the red areas ; head black in front and 

 behind, with a yellow band across the parietal shields and the 

 temples ; belly yellowish between the rings. 



Total length 550 milHm. ; tail 240. ^ 



Mexico, Guatemala, Costa Eica. '^'^ ^ - 



The individuals of this species vary immensely in the number and 

 arrangement of the annuli, as may be seen by referring to the 

 descriptions and figures quoted in the synonymy. I am therefore 

 disposed to regard the forms diastema (5 triad annuli on the body) 

 and cequalis as extreme colour-varieties of one species. I have dealt 

 in the same manner with Atractus elaps and A. latifrons, which 

 present analogous variations. 



A. Black annuli triad, with yellow interspaces. 



a. 7 to 10 annuli on the body ; irregular black blotches on the 

 red areas. 



a. S (V. 126 ; 0. 97). Mexico. 



h. <5' (V. 128; a. ?). Teapa, Tabasco. F. D. Godman, Esq. [P.]. 



c. 5 (V. 133; C. 110). Jalisco. F.D. Godman, Esq. [P.J. 



h. 8 annuli on the body ; no black spots. 



d. Yg. (V. 130 ; C. 104). Duenas, Guatemala. 0. Salvia, Esq. [C.]. 



B. 25 to 2,7 equidistant black annuli on the body. 



e. 2 (V. 133; C. 92). S. Geronimo, Guate- Eobert Owen, Esq. [0.]. 



mala. (Type of P. cequalis.) 



f. Yg. (V. 131 ; 0. 112). Vera Paz, low forest. 0. Salvin, Esq. [0.]. 



