VIPERA 233 



Coloration. — It is characteristic of this species, 

 contrary to the rule in snakes, to present such 

 marked differences of colour, according to the sexes, 

 that these can be distinguished in most cases from 

 that character alone. 



Whitish or pale grey specimens, with black belly 

 and jet black dorsal markings (Plate XII.), are males. 

 Brown and brick-red specimens, with the markings 

 of a more or less dark brown or red, are females. 

 There are also brown, reddish-brown or olive males 

 with the markings of a deep black, and grey males 

 with brown markings. A very pretty colour variety, 

 which affects only females, is olive with brick-red 

 band and spots. Some males, just before exuvia- 

 tion, have the lower surface of a pale greyish-blue 

 (Coluber cczruleus, Sheppard), with the outer ends of 

 the shields black. Specimens with yellowish-white 

 chin and throat, which may be tinged with red, are 

 females ; males have the throat black, or whitish with 

 the scales spotted or edged with black. Exceptional 

 females occur (in Carniola) which in this respect re- 

 semble the males. 



The markings vary considerably. Those on the back 

 usually consist of a wavy or zigzag longitudinal band, 

 flanked on each side with a series of spots corre- 

 sponding to its sinuses ; but this band may be partly 

 or even entirely broken up into rhomboidal or trans- 

 versely oval spots, or, losing its indentations, form a 

 straight stripe edged on each side with a yellowish 



