CHECKLIST OF REPTILES OF MEXICO 177 



25. Dark fields between dorsal light stripes unspotted and unbroken throughout 



life; entire ventrum black in adults tigris aethiops (p. 189) 



At least some of dark fields broken into rows of spots; ventrum not entirely 

 black in adults 26 



26. Middorsal dark field or row of spots distinctly wider than paravertebral light 



stripes; throat white, spotted or barred with black. 



tigris multiscutatus (p. 191) 

 Middorsal dark field or row of spots as wide as or slightly narrower than 

 paravertebral light stripes; throat and chest black; belly spotted. 



tigris gracilis (p. 188) 



27. Four longitudinal light stripes persisting unbroken in middorsum of adults, 



the dark fields between represented by rows of black spots; sides with 



bold vertical bars tigris tigris (p. 189) 



Six longitudinal light stripes persisting unbroken in adults, or, if any broken, 

 dorsal pattern generally light and without any bold markings. 



tigris marmoratus (p. 190) 



28. Anterior nasal in contact with second upper labial; femoral pores never more 



than 14 42 



Anterior nasal usually separated from second upper labial; if in contact, 

 femoral pores usually more than 14 29 



29. Enlarged scales preceding gular fold relatively small, frequently grading into 



granular scales of fold 30 



Enlarged scales preceding gular fold relatively large, abruptly differentiated 

 from granular scales of throat 31 



30. Postantebrachials enlarged; ventral surfaces light bluish in adults; juvenile 



striped pattern retained throughout life; maximum snout- vent length 70 

 mm.; dorsal scales relatively large, 50 to 70 in a transverse row between 



enlarged belly plates inomatus (p. 184) 



Postantebrachials not enlarged; belly, chest, or gular region dark (black) in 

 adults; snout-vent length reaching 95 mm.; dorsal scales 85 or more in a 

 transverse row tigris aethiops ^^ (p. 189) 



31. In addition to a dorsolateral light stripe on tail, a lateral light stripe present, 



bordered below by a black line (near base of tail) continuing onto otherwise 

 unicolor posterior surface of thigh; no light spots in dark field between 

 stripes in adults; postantebrachials not enlarged in either sex; neither sex 



dark blue or orange below sexlineatus (p. 184) 



No lateral light stripe on tail, at least not distinguishable from ventral tail 

 color; thighs mottled or unicolor, no posterior light stripe except sometimes 

 feebly mdicated at insertion of leg; light spots often present in dark fields 

 between stripes; postantebrachials distinctly enlarged generally, sometimes 

 less so in females; males frequently dark blue on belly or chest, or else cream, 

 not at all bluish 32 



32. Only 5 light lines, including a vertebral, 2 dorsolateral and 2 lateral lines 



through the ear; ventral surfaces cream even in males, never blue; light lines 

 very broad, more than half width of intervening dark spaces in adults; no 

 marking between light lines, except series of small spots in dark spaces in 



juveniles (disappearing in adults) burti (p. 185) 



Not so 33 



"Young only key out here; adults key out through couplet 16 to couplet 25. 



