754 REPORT OF NATIONAL MUSEUM, 1898. 



RHADIN^^A Cope. 



Bhadinaa Cope, Proc. Acad. Nat. Sci. Phila., 1868, p. 132; Proc. Amer. Phil. Soc, 

 1886, p. 487; Journ. Acad. Nat. Sci. Phila., 1875, p. 138. — Boulenger, Cat. 

 Snakes Brit. Mns., II, 1894, p. 160. 



Posterior maxillary teeth little louger, or not longer tliau the anterior; 

 hemipenis undivided, with more or less papillose calyces at the apex, 

 the whole calyculate surface presenting a free margin (capitate), from 

 below which the sjjines issue. Cephalic plates normal; two nasals and 

 one loreal. Postabdominal and caudal scuta divided. Scales smooth, 

 poreless; colubriform. 



This genus is represented throughout Mexico and Central America 

 by numerous species, and perhaps in South America, but the penial 

 characters of the species of the latter region referred to it are unknown. 

 None of tliem are of large size, and they frequently display ornamental 

 colors. The type is R. ohtusa Cope. 



A single species enters the United States, which has V)een found so 

 far only in the southeastern part of our country. 



Some of the species of Rhadincea have a pseudopreocular plate, a 

 character which I find generally constant. The division of the large 

 preocular is, on the contrary, inconstant. 



Boulenger has referred to this genus the species placed by Dumeril 

 and Bibron in the genus Liophis. These must be omitted, as I have 

 shown that they possess the penial characters of the Xenodontinse. 

 The following synopsis includes all the species which I supi)ose to be- 

 long to the genus so far as known: 



I. Scales in fifteen rows (eight superior labials). 



Postoculars, three; four inferior labials in contact with pregeneials; brown, 

 with dark cross-bands; a large dark spot on nape 7?. melanauchen Jan. 



Postoculars, two; four or five labials iu contact with pregeneials ; olive, with 

 alternating dark spots ; sides darker; a white line around snout. 



E. occipitalis Jan. 



II. Scales in seventeen rows. * 

 A. No pseudopreocular scale. 



a. Seven superior labials (four inferior labials in contact with pregeneials). 

 Frontal plate shorter; uroateges 58-71 ; no stripes; a black transverse 



band on occiput IL affinis Giinther. 



Frontal plate longer; urosteges 66-75; three longitudinal rows of spots 



or stripes II. pacilopogon Cope. 



Frontal plate medium ; urosteges 77; light-yellow brown; sides yellow. 



B. Jiavilatus Cope. 

 Frontal plate elongate ; urosteges 85-95; brown, sides paler; a yellow 



line around snout />'. lanreatn Giinther. 



aa. Eight superior labials (five inferior labials joining pregeneial). 



Urosteges 79; four longitudinal bands i?. rermicnJaticeps Cope. 



Urosteges 91; three longitudinal bands, the median extending to end 



i)f muzzle B.fnlvivittis Cope. 



AA. A pseudopreocular scale (eight superior labials). 

 /i. Four labials in contact with pregeneials. 



Urosteges 109; no bands on head; lips strongly black spotted; body 



ban ds obscure B. fulviceps Cope. 



Urosteges 78; a black, yellow-edged band from eye to angle of month; 

 sides dark; a yellow stripe each side of nape B. lachrymans Cope. 



