364 PROCEEDINGS OF THE NATIONAL MUSEUM VOL, 92 
prefrontal, the presence or absence of which has been used as a 
generic or group character. In the most primitive group (deppi) 
of the genus, it varies intraspecifically to a consideratle degree; in 
specimens from a single locality of at least two species it 1s com- 
pletely absent in some, well formed in others. In the next most 
primitive group (antauges) it varies greatly interspecifically; three 
species regularly lack it, while the remainder regularly have it. 
Only in the other three, more highly modified groups does the azygous 
prefrontal serve as a group character; in the locephalus and 
caeruleus groups it is regularly present, and in the wabricatus group 
it is regularly absent.'° 
All five groups of the genus are represented in Mexico by at 
least one species. The deppii group is composed of six in Mexico: 
deppii, fimbriatus, gramineus, oaxacae, taeniatus, and ochoterenai. 
Only four other names have been proposed in this group; digueti 
from Puebla (a synonym of taeniatus, not of deppii, of which it was 
described as a subspecies), auritus from Verapaz, Guatemala (ap- 
parently distinct; the type has an azygous prefrontal, contrary to 
Boulenger’s statement), vasconcelosii from Argueta, Pacific slope of 
Guatemala, and rhombifer from Panama. The latter is placed in this 
group with some hesitation, by description alone; I have seen no 
specimens. The group is the only one arboreal in kabits. The flat 
head, poorly developed lateral fold, elongate dorsal scales, and large 
size of the granular scales on the limbs as well as on the sides of the 
head and neck, characterize this group. Several species are green. 
The other 4 groups are composed of terrestrial species. The most 
primitive group (antauges) is composed of apvarently 6 species, 
in Mexico: antauges, bocourti, gadovii, modestus (type locality ap- 
parently Orizaba, not Guatemala as guessed by Cope), obscurus, and 
viridifiavus. All but one of these (gadovii) is known from so few 
specimens that further material may show that some of these names 
are based on variants. All names proposed for Mexican specimens 
appear to be valid. Extralimital are alfaroi (Costa Rica), monticola 
(Costa Rica), morelettii (Guatemala) and salvadorensis (Salvador) ; 
the first 2 appear to be identical’? and the last 2 also may prove 
conspecific with each other.’? The group is characterized by having 
a moderately well developed lateral fold (not a deep one as in the 
3 more recent groups) ; essentially a single loreal (sometimes a very 
small accessory loreal) ; supranasals present (sometimes enlarged to 
appear like a second pair of internasals); head scales flat; super- 
ciliary series complete; dorsal scales 45 or more. 
10 One specimen in 83 of the whole group has a tiny azygous prefrontal. 
4 Wettstein, Sitz. Akad. Wiss. Wien, math.-naturw. Kl., Abt. 1, vol. 143, pp. 28-29, 
figs. 1-9, 1934. 
# Dunn and Emlen, Proc. Acad. Nat. Sci. Philadelphia, vol. 84, pp. 28-30, 1932. 
