One individual was found in a low tree; the other was in a bush. Both specimens are males; the largest has a body length of 754 mm. and a total length of 1286 mm. Bogert and Oliver (1945:388) distinguished _O. aeneus aeneus_ in Central and South America from _O. aeneus auratus_ in México in that the diameter of the eye is more than the length of the internasal, whereas in _O. aeneus auratus_ the diameter of the eye is less than the length of the internasal. Stuart (1958:27) stated that on the basis of this character three specimens from Tikal in northeastern El Petén definitely were _O. aeneus aeneus_. Of the present specimens from southern El Petén, one has an internasal:eye ratio of 1.08; the other has a ratio of 0.87. A careful review of these snakes is needed to verify the validity of the characters used to separate the subspecies and to determine areas of intergradation. The local name for the vine-snake is _bejuquillo_. =Pliocercus euryzonus aequalis= Salvin Chinajá, 1; Río San Román, 1. These specimens are tentatively referred to _P. euryzonus_. KU 57160 is a female having 130 ventrals, 87 caudals, and 23 black rings on the body; KU 58150 is a juvenile having 128 ventrals, 79 caudals, and 27 black rings on the body. In both specimens the tip of the snout is yellow; a broad yellow band on the parietals and temporals is bordered posteriorly by a black band on the nape. The black rings on the body are not bordered by yellow, but black rings on the tail have yellow borders ventrally. In the red interspaces between the black rings, black flecks and spots, especially posteriorly, tend to form secondary black rings (Fig. 6a). According to Stuart (1948:71), _P. euryzonus aequalis_ has 25 to 27 black rings on the body, whereas _P. elapoides salvini_, which also occurs in El Petén, has 15 to 23 black rings. [Illustration: FIG. 6. Dorsal color patterns of _Pliocercus euryzonus aequalis_ (A) and _Micrurus affinis apiatus_ (B).] The specimen from the Río San Román contained a partly digested _Bolitoglossa moreleti mulleri_. Locally _Piocercus_ is called _coral_ or _coralillo_. =Pseustes poecilonotus poecilonotus= (Günther) Chinajá, 3; 20 km. NNW of Chinajá, 1. Two juveniles were on the forest floor; one juvenile and an adult were on low bushes. The juveniles have a tan dorsum with reddish brown blotches; the belly is gray, and the iris is cream-color above and brown below. The one adult is olive-brown above and creamy white below on the anterior three-fourths of the body; posteriorly it is black above and below. There are no paravertebral dark stripes nor pale spots on the dorsal scales. Two specimens (one juvenile and the adult) when encountered compressed the anterior part of the body laterally and struck repeatedly. Locally the adults are called _sumbadora_. =Sibon dimidiata dimidiata= (Günther) 20 km. NNW of Chinajá, 2.