40. THAMNOPH1S 831 



The ground color above is olive or greenish-yellow or 

 brown. Along the middle of the back runs a yellow line 

 of varying width. On the second and third rows of scales 

 of each side is a similar yellow line. Any or all of these 

 lines may be very indistinct or even absent. On each side 

 of the back are two series of alternating black spots, the 

 upper of which encroach upon the dorsal line. These spots 

 sometimes unite to form a zigzag band along each side, or 

 may be obscured by the darkening of the ground color. The 

 top of the head is usually light brown, with a yellow pineal 

 spot. There is a pair of large dark nuchal blotches. The 

 gastrosteges and urosteges are almost always more or less 

 marbled with black or slate, especially near their anterior 

 edges and along the middle of the belly. The chin and 

 throat normally are yellowish white. 



Length to anus 295 342 483 520 525 535 



Length of tail 97 117 175 ISO 160 155 



Variation. In one hundred snakes of this subspecies 

 the loreal is 1 1 in all specimens. Preoculars 1 1 in 

 eighty-one, or 81%; 2 2 in thirteen, or 13%; 1 2 in 

 five, or 5% ; and 2 3 in one, or 1 %. Postoculars are 3 3 

 in eighty-eight, or 88%; 2 3 in four, or 4%; 3 4- in 

 four, or 4%; 4 4- in three, or 3%; and 2 2 in one, or 

 1%. Temporals are 1+2 1+2 in sixty-seven, or 67%; 

 1+2 1+3 in twenty, or 20%; and 1+3 1+3 in thir- 

 teen, or 13%. The supralabials are 8 8 in eighty-nine, 

 or 89%; 7 8 in eight, or 8%; and 7 7 in three, or 3%. 

 The infralabials are 10 10 in eighty-six, or 86%; 9 10 

 in seven, or 7%; 10 1 1 in four, or 4%; 9 8 in one, or 

 1% and 11 11 in one, or 1%. The scale-rows are 21 

 2117 in fifty-five, or 55%; 211917 in thirty-three, 

 or 33%; 19211917 in four, or 4%; 192117 



