106 BULLETIN 199, UNITED STATES NATIONAL MUSEUM 



10. Femoral pore series closely approximated medially; two postrostrals; lateral 



scale rows parallel or nearly so; scales on posterior surface of thigh granular; 



small species scalaris (p. 136) 



Femoral pore series widely separated medially, or, if closely approximated, 

 scales on posterior surface of thigh not granular; lateral scale rows strongly 

 divergent; typically four postrostrals, sometimes three, rarely two 11 



11. Scales on posterior surface of thigh granular 12 



Scales on posterior surface of thigh not granular 15 



12. Dorsal scales highly irregular in size grammicus (p. 119) 



Dorsal scales subequal in size 13 



13. Lateral nuchal scales much smaller than and well differentiated from dorsal 



nuchal scales; scales of lateral row of dorsal nuchals enlarged, strongly 



keeled and mucronate grammicus (p. 119) 



Lateral nuchal scales not well differentiated from dorsal nuchal scales 14 



14. Throat light blue, barred or mottled with white; lateral belly patches confluent 



medially; preanal scales large, about seven in a row from a line between 



femoral pore series to anus grammicus (p. 119) 



Throat not as described or, if so, lateral belly patches not confluent medially 

 and preanal scales smaller 15 



15. Scales on posterior surface of thigh granular, femoral pore series widely 



separated medially, the folds defining the preanal area passing between the 

 femoral pore series; throat mottled with blue and white, never with a 

 distinct, blue spot medially or on either side posteriorly, graciosus (p. 118) 

 Scales on posterior siu-face of thigh not granular or, if so, femoral pore 

 series more closely approximated medially, the folds defining preanal area 



not or barely passing between femoral pore series 16 



16; Dorsal, ventral, and lateral scales subequal in size; small species, 



megalepidurus (p. 121) 



Dorsal, ventral, and lateral scales distinctly differing in size; large or small 



species 17 



17. A distinct, dark, light-bordered nuchal collar torquatus (p. 121) 



No distinct, dark, light-bordered nuchal collar 18 



18. Gular region mottled, not barred nor with a median or two lateral blue spots 



posteriorly torquatus (p. 121) 



Gular region not mottled 19 



19. Gular region barred in males and lacking a median posterior dark blue or 



black spot spinosus (p. 110) 



Gular region not barred; or, if barred, with a median posterior dark blue or 

 black spot 20 



20. Gular region barred in males, with a median posterior dark blue or black spot. 



undulatus (p. 117) 

 Gular region not barred 21 



21. Supraoculars large, separated from superciliaries by no more than one com- 



plete and one incomplete row of small scales; and one or more of the posterior 



supraoculars in contact with median head scales 28 



Supraoculars large or small; if any of the posterior supraoculars are in con- 

 tact with median head scales, the supraoculars are separated from super- 

 ciliaries by three or more complete or incomplete rows of small scales 22 



22. Males lacking lateral belly patches vmdulatus (p. 117) 



Males with lateral belly patches 23 



23. A pair of dark blue or black spots on posterior part of gular region. 



undulatus (p. 117) 

 No pair of dark spots on posterior part of gular region 24 



