434 EXTERNAL ANATOMY OF INSECTS. 
therefore divides them into zncisive or cutting, laniary 
or canine, and molary or grinding teeth. He denomi- 
nates those zvcisives that are broad, having in some de- 
gree the shape of a wedge, their external surface being 
convex, and their internal concave ; whence they are evi- 
dently formed for cutting. The /aniaries are those which 
have a conical shape, are often very acute, and in gene- 
ral the longest of any; and in some insects, as the carni- 
vorous Orthoptera (and the Libellulina), they cross each 
other. The molaries are the largest of all, and their 
purpose is evidently to grind the food. ‘There is never 
only a single one to each mandible, while the number of 
the incisives and laniaries is very variable. As the mo- 
laries act the principal part in mastication, they are 
nearer the inner base of the mandible or point of sup- 
port: they serve to grind the food, which has been first 
divided by the incisives or torn by the laniaries. The 
carnivorous tribes are destitute of them; in the omnivo- 
rous ones they are very small, and in the herbivorous 
they are very large*. So that in some measure you 
may conjecture the food of the animal from the teeth 
that arm its mandibles. Of incisive teeth you may find 
an example in those that arm the end of the mandibles 
of most grasshoppers (Locusta), and of the leaf-cutter- 
bees (Megachile)»; of the laniary or canine teeth, you 
will find good examples in the mandibles of the dragon- 
flies (Libellulina); the two external teeth of the apex 
of those of the leaf-cutter bees may be regarded as be- 
tween the incisives and laniaries; and the pointed man- 
dibles without teeth may be deemed as terminating in a 
* Comparaison des Organes, &c. 7—. 
> Prats VI. Fig. 6. and XIII. Fre. 5. a”. 
