REVISION OF THE KING SNAKES. 141 



shields usually a little shorter than anterior, in contact with each 

 other, or occasionally separated by 1 or 2 small scales. The maxi- 

 mum number of scale rows is nearly always 23 or 21, becoming 

 posteriorly 19 or 17, but examples from Costa Rica and Yucatan may 

 not have more than 19 rows. 



The proportions are nearly the average for the genus. The head 

 is widest at the temples and tapers toward the snout, which is blunt; 

 it is but slightly distinct from the body; the latter is cylindrical, 

 fairly stout, and of approximately uniform diameter; the tail is 

 short and stout, but averages a little longer than for most forms 

 of the group; its length in proportion to the total length varies 

 from 0.124 to 0.164 (males, 0.130 to 0.164, average 0.144; females 

 0.124 to 0.140, average 0.131). The largest specimen examined was 

 1,580 mm. in length, and was from Nicaragua; however, a dried 

 skin of one from the same country measured 1,610 mm. 



The body pattern is made up of from 17 to 37 paired rings of 

 black bordering narrow annuli of white or yellow and separated 

 by broader ones of red. The dorsal scales of the red areas are 

 usually strongly tipped with black, but these black tips are some- 

 times very small or absent altogether. The white rings are 4 to IJ 

 scales in width, widening but little if any on the first row of scales; 

 the black rings are from IJ to 3 scales wide on the middorsal line, 

 and, rarely, excluding the red altogether from some of the annuli. 

 The red rings, although not infrequently narrower, are usually 

 wider than the groups of black and yellow rings that separate them. 

 The scales of the yellow rings may be uniform in color, but more 

 often they are strongly tipped and mottled with black, and infre- 

 quently the latter color may almost obliterate the yellow. 



All of the annuli are usually continuous across the belly, but some 

 specimens from the State of Vera Cruz and from Yucatan Peninsula 

 show the red bands to have widened on the sides so far as to exclude 

 the black and yellow annuli altogether from the belly. The yellow 

 then appears in dorsal semicircles, bordered with black. (Further 

 change in this direction probably accounts for Boulenger's variety 

 E, 1894, 205.) In a few specimens the belly is much overspread 

 with black, but usually the black is conspicuous only as a blotch 

 in the yellow rings, and it may be absent even there. 



The head is black except for a more or less perfect cross band of 

 white or yellow on the snout, chiefly on the prefrontal plates. It is 

 sometimes much reduced, and rarely absent. On top of the head 

 the black extends back to the posterior portion of the parietal plates, 

 on the supralabials it extends as far back as the fifth. The first black 

 band is close behind the parietals, or involves the tips of these plates, 

 and in the great majority of cases is continuous across the throat. 



