Mexico and Cenfral America 



and there is no distinctive pit on the side of the 



liead. 



KEY TO GENERA In general coral snakes have rings of red, black, 



and yellow, but in some species the yellow may be 



The poisonous snakes of this region belong to almost white, in others the red is aljsent except 



two families, the I^lapidae, which is represented on tlie head and tail and one is black and red only 



by two genera of coral snakes, and the Crotalidae, (brown and white in preservative). In the tri- 



represented by five genera. The latter are easy color species tJie black rings may occur singly, 



euougli to distinguisji by the presence of the loreal separated from one another l)y rings of yellow 



pit on the side of the face (fig. 4), a broad and red. or in groups of three (triads), each triad 



head which is distinct from a narrow neck, and se])ai'ated by broader rings of red. The harmless 



tlie eye with a vertically elliptical pupil. How- mimics of tliese coraTsnakes, such as the tropical 



ever, there are several kinds of nonpoisonous forms of tiie milksnake (Lampropeltk trkingu- 



snakes that look veiy much like the coral snakes him) and tlie members of such ti'opical genera as 



and the latter have few easily visible features that Fliocercii\ tend to luive the black rings of their 



absolutely distinguish tliom. Coral snakes have patterns jxiired. They also tend to liave longer 



a relatively narrow, though often flattened, head tails than the short-tailed coral snakes. However, 



that is not distinctly set o\\ from the slender and any l)rightly-ringed snake should be treated with 



cylindrical body. The eye is small and has a respect until its identity as a harmless species is 



round puj)!! (as do most nonpoisonous snakes) confirmed. 



1. A. Dorsal scales at midbody distinctly keeled 7 



B. Dorsal scales at midbody smooth 2 



2. A. Pupil of eye vertically elliptical XP* 



B. Pupil of eye round 3 



3. A. A loreal scale present (3 scales between nostril and eye) NP 



B. No loreal scale 4 



4. A. Color pattern of body made up of alternating rings of 



red, yellow, and black (red and black in one species) 5 



B. Color pattern not in rings XP 



5. A. Black rings altei'uating with yellow; OR single, sepa- 



rated by broad bands of red and yellow; OR in 



triads separated by broad bands of red 6 



B. Black rings in pairs XP 



6. A. Entire snout and main part of head black; first band 



after yellow neck ring red Micruroides 



B. Usually some light color anterior to eyes; first band 



after red or yellow neck band black Micrunis 



T. A. A loreal pit present 8 



B. Xo loreal pit XP 



8. A. End of tail with a jointed rattle 11 



B. No rattle 9 



9. A. Crown of head with nine regular plates Agkistrodon 



B. Crown of head with small scales or irregular plates 10 



10. A. Subcaudals near tip of tail divided and elongated to 



form spiny burr (Fig. 32) Lachesis 



B. Scales near tip of tail not greatly dift'erent from those 



nearer base BotJirops 



11. A. Crown of head with nine regular plates Sisfiniru-s 



B. Crown of head with small scales or a few irregular plates Crotalus 



• NP = Nonpoisonous 



51 



