92 HUNTING, PASTORAL, AND AGRICULTURAL ANTS. 
domesticated certain species of aphides, and may be 
compared to the pastoral stage of human progress—to 
the races which live on the produce of their flocks and 
herds. Their communities are more numerous; they 
act much more in concert; their battles are not mere 
single combats, but they know how to act in combina- 
tion. I am disposed to hazard the conjecture that 
they will gradually exterminate the mere hunting 
species, just as savages disappear before more advanced 
races. Lastly, the agricultural nations may be com- 
pared with the harvesting ants. 
Thus there seem to be three principal types, offer- 
ing a curious analogy to the three great’ phases—the 
hunting, pastoral, and agricultural stages—in the 
history of human development. 
