198 BULLETIN 114, UNITED STATES NATIONAL MUSEUM. 



District of Columbia average still lower than in New England and the 

 Alleghenies, and it is here that the lowest point of all, 19-17, is 

 attained. 



Of other features of the scutellation the temporals are perhaps the 

 most variable. The normal number for the group and for the genus 

 is 2 + 3+4, but in this group in particular a reduced number is very 



Ventral 

 plates. 

 216 



210 



204 



198 



192 



186 































































































































' 















































































180 



In- North- Wis- Mich- Can- New South- East- NJ. D.C. Ohio. West- Alle- N. C. Ten- Fla. 



diana. ern con- igan. ada. Eng- ern ern Del. 23 7 em ghen- S.C. nes- 3 



19 HI. sin. 61 6 land. N.Y. Pa. 14 Pa. ies. 3 see. 



10 16 63 25 19 52 19 6 

 Localities, and ntjmbees of specimens. 



Fig. 56.— Diagram sho-wing geographic variation in number of ventral plates in Lampropeltis 



triangulum triangulum. 



frequent — the last row is oftenest reduced by one, the second row 

 less often so reduced, and the first row is the most constant. The 

 specimens from the District of Columbia show the greatest reduction 

 in temporals. The accompanying table gives at a glance the aver- 

 ages to two places of decimals, of the temporals in the first and 

 third rows for Missouri, Massachusetts, and the District of Columbia. 





Temporals 



of the 

 first rov . 



Temporals 



of the 

 third row. 



Syspila in Missouri 



L88 

 1.94 



L63 



3.65 

 3.83 



3.26 



Triangulum in Massachusetts. 



Triangulum in District of 



Columbia 





