292 



REPTILIA: SERPENTES: COLUBRIDAE 



TAN TILL A 



TANTILLA Baird and Girard 



1853 Tant i 11a Baird and Girard, Cat. N. Amer. Rept.: 131. Type-species: Tant i 11a coronata Baird and 



G irard. 



1854 Homalocran ion Dumeril, Mem. Acad. Sc i . Paris, 2y. li^^. Type-species: None given, 



1860 Lioninia Hallowell, Proc. Acad. Nal. Sci. Phila., 1860; 484. Type-species: Lioninia vermiform i s 



Hallowell. 

 I863 Homalocran i urn Gunther, (emendat i on of Homalocran i on Dumeril), Ann. Mag. Nat. Hist., (3) 12: 352. 

 I872 Microdromus Gunther, Ann. Mag. Nat. Hist., (4) 9; I7. Type-species: Microdromus viraatus 



Gunther. 

 I894 P ogonasp i s Cope, Proc. Acad. Nat. Sci. Phila., 1894: 204. Type-species: Poqonaspis ruficeps 



Cope. 



Distribution: Southern United States through Central America and South America to northern 

 Argent ina. 



Content: About 47 species, of which 25 occur within limits defined for this work. 



Key to the species 



Clave de especies 



1. With two pairs of chinshields- 

 With one pair of chinshields — 



ruf iceps 



2. Without white collar on neck 3 



With white neck collar, about six scale rows 



wide suprac i ncta 



3. Lacking two longitudinal black stripes 



vent rally 4 



With two longitudinal black stripes on 

 ventei v i rgata- 



4. Some combination of labials other than fourth 



and fifth entering orbit, usually third and 

 fourth 5 



Fourth and fifth supralabials in orbit 



tr i taen iata 



5. Dorsal pattern not made up of transverse, 



alternating light and dark bands 6 



Dorsal pattern entirely of alternating, 

 transverse, light and dark bands sem i c incta 



6. First pair of infralabials not in contact 



on m idl tne 7 



First pair of infralabials in contact on 

 midline 15 



7« Dorsum not olive, head and neck not ivory 8 



Dorsum uniform olive; head and neck ivory 

 coloi alb iceps 



8. Dorsum not white with small black spots 9 



Dorsum white with small black spot s- vermi form is 



1. Con dos pares geneiales- 

 Con un par geneial 



- ruf iceps 



9. With fewerthan 5" caudals- 

 With more than 5" caudals- 



-10 

 -13 



10. Fewer than 120 ventrals 11 



More than 120 ventrals 12 



11. Head shields with light borders and centers 



ca nula 



Head shields without light borders and centers- 

 brev i s 



12.Maxillary teeth anterior to diastema 12 — ba ird i 



Maxillary teeth anterior to diastema 14 



sch istosa 



2. Sin collar nucal bianco del ancho de seis 



e sea mas 3 



Con collar nucal bianco del ancho de seis 

 e sea mas suprac i ncta 



3. Sin dos cintas long i tudi nales ventrales 



negras 4 



Con dos cintas long i tudi nales ventrales 

 negras > v irqata 



4. Otra combinacion de supralab iales, no cuarta y 



quinta entrando en la orbita, generalmen te, 



tercera y cuarta 5 



Cuarta y quinta supralabial entran en la 

 orb i ta tr i taen iata 



5- Sin diseflo dorsal formado por cintas Claras y 



negras transversas, alternas o 



DiseRo dorsal formado totalmente por cintas 



Claras y negras transversas alternas 



sem ic incta 



6. Primer par de I nf ralab iales no coatacta entre 



sr -7 



Primer par de i nf ralab iales contacta entre s' — 

 15 



7. Sin dorso oliva ni cabeza y nuca en color 



marfil 8 



Dorso oliva; cabeza y nuca en color marfil 



albiceps 



8. Dorso no bianco con peque?ias manchas negras 9 



Dorso bianco con pequeRas manchas negras 



verm i form i s 



9. Con menos de 5'' caudales- 

 Con mas de 5^^ caudales 



10. Menos de 120 ventrales- 

 Mas de 120 ventrales 



-10 

 -13 



-11 

 -12 



ll.Escudos cefalicos con hordes y centros claros — 



canula 



Bscudos cefalicos sin hordes ni centros claros- 

 brev i s 



