Another small group of mildly poisonous snakes is found along the Mexi- 
can border of the United States. They have grooved tceth in the rear of the 
upoer jaw and can scarcely be consiccred dangerous to man. This group: in-— 
cludes the lyre snake (Trimorphedon sDD.), the cat-eyed sneke (Leptodeira 
septentrionalis), the black-banded snceke (Coniophanes imperialis), and the 
Arizona vine snake (Oxybelis microphthalmus). . 
Key to the Principal Poisonous Snakes of the United States 
smoouh-scalled snakes, characterized by brilliant’ colors; markings consisting 
of broad alternating rings of crimson and black, separated from each other 
by narrower yellow rings; black bands as broad as the crimson; a pair of 
short, erect longitudinally grooved fangs in front of upper jaw; head as 
WGlemels) MCCeislelelc eleieietele + etsle eleisisie'cie se COre kk, Or harlequin, saakkes—— iii API AR; 
Head black in front, a yellow band across center and behind this a 
black ring; yellow body rings very narrow. lost common in the Gulf 
Suawes, bub exmuending north to North Carolina, and in the Milssissappa 
Valley casually northward to Indiana. 
dere ciele ciel! atmieieielsios eres eins VOL orm Haiwlequaimy) Siac ——lkeigutgiis aUELVALUIS). 
Head black over greater portion; yellow band on back of head and 
behind this a red ring; yellow body rings broader. Southern New 
Mexico, Arizoné, Tiburon Island in the Gulf of Californie, and 
northern Mexico in region bounded by Rocky Mountains and Colorado 
RANE L aialaletelele/sielielciels sisi) s/o SONOLAn, COnal, Snake——Maic ruroudes) ecunyxamuhus.. 

Keeli-scaled snakes, characterized by duller ‘colors; markings not forming 
regular alternating bands, but consisting of blotches, diamonds, or in- 
complete bands; a pair of long, hollow, freely.movable fangs that fold 
back against roof of mouth when jaws are closed; deep pit on face between 
nostril and eye; scales on upper parts keeled; pupils elliptical in shape, 
vertical in position; head wider than neck......"Pit vipers!—-CROTALIDAL. 
Tail without rattle, ending in a point; top of head covered with 
SOT SLICES SS Os CACC CNS ee Te oon IE Ares EL Ay DEN UR ARES my W or <aRLS De OKG (OMAN 
Color pattern distinct; ground color pale brown (in Texes grading into 
pale green on tail), with large dorsal blotches of darker chestnut 
brown (usually in the form of a butterfly with outspread wings). 
Massachusetts to northern Florida, westward to Illinois, Kensas 
and TexaS.-ececseose..oe----Copperhead, highland moccasin, chunkhead, 
poplar leaf, or deaf adder—Agkistrodon mokasen. 
Color pattern obscure; ground color light to dark brown; cross bands 
darker, often indistinct and bordered with yellow spots; some of 
ventral scales on teil undivided. Lowlands from southeastern 
Virginia to Florida and the Gulf-States northward through the 
Mississippi Valley to southeastern Missouri and southern 
T1linois.s.-ecces».COtton—mouth water moccésin——Agkistrodon piscivorus. 
Te RU yale ae aUTy Sha I Aas ON ee rte ere a eo a Sloe ngADia DNs} SudlOen On GONE ue bus) 
A single large scale on top of head between supra— 
ocular Seales (hose ovier. Sve)! cS ccieie sic cine erevosienyaielsielndo USmaUGUS.s 
Many small scales on top of head between supraocular 
Seales) (UAOSe. OVET) yes) asses bisieiayaleielaiere)> eidieia\ereieiorele piemieroine CRO UGLUS, 
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