82. UROTHECA. 183 



Liophis tricinctus, Jan, Arch. Zool. Anaf. Phijs. ii. 1863, p. 301, cmd 



Icon. Gen. 18, pi. iv. fio-s. 4-6 (1866). 

 Pliocercus dimidiatus, Cope, Proc. Ac. Philad. I860, p. 190, and 



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



xxii. 1885, p. 183. 



saro;ii, Fisch. Arch.f. Nat. 1881, p. 225, pi. xi. figs. 1-3. 



Liophis elapoides, Garm. N. Am. Rept. p. 69 (1883) ; Bocourt, Miss. 



Sc. Me.c, Rept. p. 035, pi. xli. fig. 6 (1886). 



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



Elapochrus aequalis, Giinth. Biol. C'.-Ain., Rept. p. 106, pi. xxxvi. 



fig. A (1893). 

 dimidiatus, Giinth. I. c. p. 107. 



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

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

 the praefrontals ; 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 prjeoculars 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 chin-shields, which, 

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

 124-143 ; anal divided ; subcaudals 85-127. Red 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 millim. ; tail 240. 



Mexico, (iuatemala, Costa Rica. 



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 ela^s 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; C. 97). Mexico. 



fc. cT (V. 128; 0. ?). Teapa, Tabasco. F.D.Godman,Esq.rP.]. 



c. $ (V. 133; C. 110). Jalisco. F.D.Godman,E8q.[P.]. 



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



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



B. 25 to 27 equidistant black annuli on the body. 



e. 2 (V. 133; C. 92). S.Ger6nimo,Giiate- Robert Owen, Esq. [C.]. 



mala. (Tvpe of P. ceqiialis.) 



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



