210 
SYSTEMATIC ARRANGEMENT. 
serrations be correct, which they are admitted to ho 
in general, the mandibular 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 tbis 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 ar& 
