30 NORTH AMERICAN INSECTS. 
the one undoing what the other does; the injuries which 
one species would inflict upon man are checked by other 
species, which prevent their superabundance, and keep an 
even balance in the scale of being. 
Hence this law of antagonization is, in its effects, the 
law of Compensation. Thus we see Tiger Beetles, Carabi, 
Lady-birds, and many other Coleoptera, destined to benefit 
mankind by devouring other insects which are noxious. Of 
these we have already spoken. But a mere negative use- 
fulness is not the only one belonging to this order. There 
are also many other Beetles which render us the greatest 
service by devouring putrid substances, carrion, decomposed 
fermenting plants, mushrooms, dung, and decayed wood, as, 
for instance, the Dung Beetles, Carrion Beetles, and many 
others. 
Now the food of Beetles in general has suggested to us 
the idea of dividing them into three Natural Families, ac- 
cording to the nourishment which they subsist upon, and 
this division seems to us the simplest, most uniform, and 
the most rational, as well as the only really natural divi- 
sion. Accordingly, T classify all the Coleoptera under one 
of the three following families: 
1. Carnivorous Beetles, which, like Lions and Tigers among Beasts, 
prey upon living Insects; as presented in Figure 3. 
2. Scavenger Beetles, which live on putrid matter, carrion, decayed 
wood, and plants; as those represented in Figures 6, 7, 8, 9, and 
10. 
3. Herbivorous Beetles, which feed on Plants and Fruits, as Snout 
Beetles, or Weevils, Capricorn Beetles, ete. 
The first two families are useful to man, and deserve our 
protection; but the last are noxious, and should be de- 
stroyed wherever encountered. 
The distinguished French Entomologist, Latreille, divided 
Beetles into five tribes, according to the number of joints 
found on their feet. Thus he called those that have five 
