98 THE SNAKES OF SOUTH AFRICA. 



to an extreme and will doubtless create endless confusion and 

 labour in the future, if continued. In the case in point the 

 difference is probably a matter of variation which is by no 

 means constant. Naturall}', if a large series should be ex- 

 amined, and if the difference be seen to be constant, then there 

 is justification for the creation of a new species and sub-species, 

 not otherwise. 



The generic name Simocephalus has been previously used for a 

 genus of Crusiaceansi, and will require to be altered. 



The Mole Snake. 

 Also known as the Zwart Slang, Lui Slang, Mol Slang. 



{Pseiidaspis cana.) 



The Mole Snake is widely distributed over South Africa. 

 It varies considerably in colour. Some specimens are shiny black, 

 others brick red, or brown spotted with black. The Mole Snakes 

 and House Snakes can be regarded as typical examples of non- 

 venomous snakes. Young Mole Snakes are brown, with irregu- 

 lar black markings. Many of these about two feet long are light- 

 brown with wavy black markings on the back, and are also spotted 

 and blotched with white. Adults are usually found most 

 abundantly about the haunts of moles, mole-rats, field-rats and 

 vlei otomys, in sandy soil, sparse^ covered with scrubby bush. 

 The young liaunt stony hillocks, and rough, rock-strewn ground, 

 in pursuit of lizards, on which they mostly feed. In captivity. 

 Mole Snakes usually refuse all food. Occasionally I have induced 

 them to eat, and have observed them constrict and swallow mice 

 and rats. 



Mole Snakes, when surprised, will show fight, boldly facing 

 the intruder and making desperate lunges in his direction, with 

 gaping mouth and slightly raised body. This habit of raising 

 the fore part of the body and head, and general outward similarity 

 to the Cape Cobra, causes them to be mistaken usually for the 

 latter. Apart from the difference in the formation of the teeth 

 and scales, Mole Snakes can easih' be distinguished from cobras. 

 Their heads are narrow, and join the body without any narrowing 

 at the neck region. Their bodies are nicel}^ rounded (cylindrical), 



