13. COLUBRID^ 



course, that it was a perfectly harmless snake, its sudden 

 aggressiveness combined with its horrid appearance nearly 

 secured its release before I could overcome my instinctive 

 repugnance. 



180. Thamnophis sirtalis parietalis (Say) 

 Prairie Garter Snake 



Coluber parittalis. Say, Long's Exped. Rocky Mts., Vol. I, 1823, p. 186 

 (type locality, West side of the Missouri River three miles 

 above the mouth of Beyer's River). 



Eutaenia parittalis Cope, .^nn. Rep. U. S. Geol. Surv. Terrs., 1871 (1872), 

 p. 468. 



Eutaenia ornata Yarrow, Surv. W. looth Merid., Vol. V, 1875, p. 553. 



Thamnophis parietalis Van Denburgh, Occas. Papers Cal. Acad. Sci., 

 Vol. V, 1897, p. 200 (part); Ellis & Henderson, Univ. Colorado 

 Studies, Vol. X, No. 2, 1913, p. 86, pi. IV, fig. 19; Ellis & Hen- 

 derson, Univ. Colorado Bull., Vol. XV, No. 6, 1915, p. 261. 



Eutaenia sirtalis parietalis Taylor, Ann. Rep. Nebr. State Board Agric. 

 for 1891, 1892, p. 325; Cope, Report U. S. Nat. Mus. for 1898, 

 1900, p. 1077 (part); Branson, Kansas Univ. Sci. Bull., Vol. II, 

 No. 13, 1904, p. 366, fig. 5; Ditmars, Reptile Book, 1907, p. 237, 

 pi. LXXII, fig. I (part). 



Thamnophis sirtalis parietalis Ruthven, Bull. U. S. Nat. Mus. No. 61, 

 1908, p. 166 (part); Cockerell, Univ. Colorado Studies, Vol. 

 VII, No. 2, 1910, p. 131; Van Denburgh & Slevin, Proc. Cal. 

 Acad. Sci., Sen 4, Vol. 5, No. 4, 1915, p. 108; Stejneger & Bar- 

 bour, Check List N. Amer. Amph. Rept., 1917, p. 103 (part); Van 

 Denburgh & Slevin, Proc. Cal. Acad. Sci., Ser. 4, Vol. 8, No. 6, 

 1918, p. 190; Ruthven, Occas. Papers Mus. Zool. Univ. Michigan, 

 No. 66, 1919, p. 3; Van Denburgh & Slevin, Proc. Cal. Acad. 

 Sci., Ser. 4, Vol. XI, 1921, p. 40. 



Description. — Head distinct from neck, flat-topped, with 

 narrow, rounded snout, and temporal regions sometimes 

 swollen. Eye large. Rostral plate large, bounded behind 

 by internasal, anterior nasal and first labial plates. Plates 

 on top of head, a pair of internasals, a pair of prefrontals, 

 a frontal, supraocular of each side, and a pair of parietals. 



