210 SYSTEMATIC ARRANGEMENT. 



serrations be correct, which they are admitted to be 

 in general, the mandihular teeth of the Orthoptera 

 offer this peculiarity, that they have a coriaceous and 

 transverse plate, (lame) at their base, which seems 

 to separate them from the body of the mandible ; 

 whereas in other cases, the teeth are well known to 

 be only projecting pieces of the substance of these 

 organs. The same observer, adopting an idea first 

 started by Knoch, regards these dentations as bearing 

 so close a relation to the mode of nourishment, that 

 by observing their structure, distinct intimation may 

 be obtained of the kind of food used, and conse- 

 quently in some degree of the habits of the respec- 

 tive species. He divides them according to their 

 analogy to the dental system of mammiferous ani- 

 mals, into incisive, canine, and molar. The former 

 are large, somewhat resembling a curved wedge, their 

 external surface convex, and the opposite one con- 

 cave ; a form which renders them eminently fitted 

 for cutting : the teeth at the extremity of the 

 mandibles of Locusta exemplify this modification. 

 The canine teeth are conic, often very sharp, and 

 lengthened, and are of course characteristic of such 

 genera as Empusa and Mantis, which are purely 

 carnivorous. The molars are large, short, and fitted 

 for bruising alimentary substances. Never more 

 than one exists in each mandible situated at the base 

 opposite to each other. The species provided with 

 the first and last mentioned description of teeth are 

 herbivorous; and when they exist simultaneously, 

 which happens occasionally in such species as 



