110 HELICOPS ERYTHROGRAMMUS. 
one nearly six, while the Tropidonotus bipunctatus (sirtalis) never reaches four 
feet in length. The two animals also differ entirely in colour, and this is even 
uncommonly well marked in Daudin’s plate. The one has the body dusky, with 
pale yellow longitudinal lines; the other is bluish-black, with longitudinal lines of 
red, so remarkable as to afford a specific character;* an arrangement which never 
occurs in any serpent of this country, and as far as my observations have 
extended, never in any other. 
Schlegel further believes that the Helicops erythrogrammus is a variety of the 
Homalopsis (Helicops) plicatilis, the result of climate, to which I can by no 
means consent, as they differ greatly in several particulars. The Helicops 
plicatilis is reddish-brown above, more or less shaded; the Helicops erythro- 
grammus is deep bluish-black, with three bright red longitudinal lines; the former 
has a single anterior frontal plate, the latter has two; the one inhabits South 
America, and the other is found only in the United States. 
~ Serpent 4 rales rouges. 
