162 Wisconsin Academy of Sciences, Arts and Letters. 



specimens of C. tergeminus which I have seen from Wisconsin, have a 

 broader head and the transition from the head to neck is more abrupt 

 than in Ilhnois or Ohio specimens." 



It is safe to assume, then, that all snakes that have a triangular head, 

 that may be met in this state, are to be avoided. 



FAMILY COLUBRIDJE. THE COLUBRINE SNAKES. 



Eepresented by eleven genera, twenty species and several varieties. 

 The following Key for the determination of the genera is a modification 

 of that used by Jordan, Smith, and others. 

 Dorsal scales carinated, a. 

 Dorsal scales smooth, i. 

 a. Post-abdominal scutella entire, b. 



a. Post-abdominal scutella bifid, c. 



b. Dorsal rows of scales not exceeding 23 Entos,nia^ 



b. Dorsal rows of scales exceeding 25 Pityophis. 



c. Loral and anteorbital plates, both present, d. 



c. Loralsabsent Storeria. 



d. Dorsal rows of scales, 19 or more, e. 



e. Cephalic plates typical, f . 



e. Cephalic plates not typical, large, h. 



f. Post-orbitals three, rarely two; ante-obitals usually one; dorsal rows of 



scales, 23-29 Tropidonotus. 



t. Post-orbitals two; dorsal rows of scales, 19-21 Regina. 



h. Muzzle projecting and recurved Heterodon. 



h. Muzzle not projecting Coluber. 



i. Ante-orbital plates both present, j. 



j. Post-abdominal scutella entire or bifid; dorsal rows of scales 25 Ophibolus. 



j. Post-abdominal scutella bifid ; dorsal rows of scales not exceeding 21 , k. 



k. With yellow ring around the neck Diadophis. 



k. Without a ring around the neck, 1. 



1. Dorsal scales in 15 rows , Liopeltis 



1. Dorsal scales in 17 or more rows Bascanion. 



EUT^NIA, B. & G. 



Our most common snakes; terrestrial; ground color dark; one vertebral 

 and two lateral stripes; gastrosteges 140-170; urosteges 50-120; dorsal rows 

 of scales 19. 



It is believed that the following Key will enable one to trace any species 

 or form commonly found, though great variations in the markings exist. 



(a) Lateral stripe on the third and fourth rows of scales: body slender; tail 



nearly one-third of total length, (b). 

 (a) Lateral stripe on second and third rows of scales; body stouter; dorsal 



band on one and two half rows of scales; tail one-fourth of total length; 



G. 132-170; U. 55-80 Sirtalis. 



(a) Scales rough; stripes all narrow; lateral not usually over a scale in width, 



placed on part of two rows; six or seven series of brownish or blackish 



spots; outer row of scales often very broad , Badix- 



