630 NORTH AMERICAN SNAKES COPE. 



lateral yellow stripe more distinct by the suffusion of the third, second, 

 and half the first rows with brown, thus prodticinj;- an appearance much 

 like that of the i>. laterale. But only the third and fourth rows bear 

 the yellow stripe, and the brown band covers the ends of the gastros- 

 teges in that species. It was this resemblance that induced me to com- 

 bine the two species, with the remark (Proc. Acad. Phila., 18GG, p. 305) 

 "Tlie young of the form lateralis, the adult, the tneniatus." 

 The measurements of the tail in nine specimens are as follows : 

 Tiiree and one-seventh times in total length, Nos. 8432 and 4384 ; 

 31, 9520, 8120, and 11422; 3^, 13618 and 1979; 3^, 8122; 3^, 1983. 



COLUBER Liuu. 



Systeitia Naturse, ed. xii, 1766, p. 377, pt. ; Oppel, 1811, pt. Boie, Isis von Oken; 

 1827, p. 209 ; Giinther ex Liuu., Cat. Suakes Brit. Mus., 1858, p. 87 ; Cope, Check 

 ListN. Amer. Batr. Rept., 187;"), p. 39 ; Proc. U. S. Nat. Mus., 1888, p. 390. Calopeltis 

 Bouap.,Mem. Real. Acad. Torino (2), 11, 431, 1840. Scotophis Bd. aud Gird., Cat. 

 N. Amer. Rept., Serpents, 1853, p. 73. Nairix Cope ex Laurenti, Proc. Acad. 

 Phila., 1862, p. 338 ; Cat. Batr. Rept. Centr. Amer., Mex., 1887, pp. 56-71. 



Colubrid suakes, with equal teetli, subcylindric body, and two rows 

 of caudal scutella. The pupil round ; the rostral and nine superior 

 cephalic shields normal; two nasal and one preocular phite. Two 

 pairs of geneials ; scales of the body with two apical pits, keeled or 

 rarely smooth. Preanal shield divided. 



This genus embraces a number of species of the northern temperate 

 regions of the world. Six species belong to Eurasia and ten to North 

 America. Three others extend to within the tropics of Mexico aud 

 Central America. 



The North American species are of inoffensive habits, but are destruc- 

 tive to birds and small mammals. Some of them reach considerable 

 dimensions, but they are exceeded in this respect by some of the spe- 

 cies of the allied genus Spilotes. The G. guttatus and C. rosaceus are of 

 brilliant colors. 



Tlie North American species are closely allied, and form gradations 

 of characters which must be carefully estimated in order to learn the 

 definitions. It is not difficult to distinguish the G. vulpimis, G. guttatus, 

 and G. cmoryi, but the group of which the G. spiloidcs is the type is 

 more dillicult to unravel. It embraces that species, G. conjims, G. qiiad- 

 rivittatus, G. ohsoletus^ and G. Uctus. All the North American species 

 (except, possibly, G. conjiriis, of which but one specimen is known) 

 have twenty-seven rows of scales, some species {G. vulpinus) varying to 

 twenty-fiv^e, and others (C emoryi) varying to twenty-nine. The most 

 important characters are the number of rows of scales which are keeled, 

 and the length of the tail, as indicated by the number of urosteges. 

 The coloration has a typical value, but displays many transitions, espe- 

 cially in the spiloides group. 



1 present a synopsis of the principal characters in the following table. 

 Three neotroi)ical species are included in it: 



