REVISION or THE KING SNAKES. 163 



ity of forms in the genus. The important thing to note in all these 

 matters of structm-e is that annulata is typical of the co^iservative 

 forms thi'oughout the genus. It is not specialized by having a very 

 short tail (jaicroyliolis) or ver}'' long one (pyrrJiomelaena) , in havijig 

 the temporals reduced in number (elapsGides, microplwUs) or irregular 

 (tnangulum), in havmg a high number of labials (j^yrrhomelaera, 

 conjuncta) or a low number {elapsoides , rhomhomaculata) , in havmg 

 unusually short postgenials (h&i'lii, calif orrnae), in having a low scale 

 formula (elapsoides, micropholis, holbrooJci), or in having a low number 

 of ventrals (elapsoides, gentilis in Utah). It is near to the normal or 

 average for the genus. 



The pattern, too, is one from which the patterns of all the northern 

 members of the group may be derived. This will be made m.ore 

 plain later on, but it will be well here to describe the pattern of the 

 Puebla specimen (tig. 66), since this is theoretically the most primi- 

 tive in the group (no. 9555, Mus. Comp. Zool., Puebla, Mexico). It 

 has 19 white (m alcohol) rings on the body and 4 on the tail. These 

 are 1| to 2 scales in -v\ idth, are a little mottled with darker, chiefly on 

 the sides, and encircle the body. The space between the white rmgs 

 may be described as black, more or less split with red. The red never 

 extends onto the belly beyond the tips of the ventrals, and dorsally 

 it narrows toward the median line and is frequently excluded there- 

 from by a Vv'idening of the black borders. The tail is ringed with 

 black and white. The head is black as far back as the middles of the 

 parietals, anterior temporals, sixth supralabials and fifth infralabials, 

 except for small irregular spots of lighter on the prefrontals and 

 anterior part of frontal, and in the loreal region. This last is sug- 

 gestive of the light cross band on the snout of polyzoiM, but it is too 

 much to say now what its significance may be. It is expected to be 

 shown that all the forms of the group north and west of ammlata may 

 be easily derived from such a pattern as this. 



About all that can be definitely said of the relationshi]) of this form 

 to those mhalnthig adjacent ranges is that it is a direct relati\'e of 

 nelsoni, and of gentilis. It is a fairly safe conclusion that mter- 

 gradation takes place with both of these form.s. Its relationship to 

 polyzona., judging from the material now at hand, is not at all clear, 

 but it must be close. 



