"Harvester Ants or Agricultural Ants" (Pogonomyrmex spp.)

There are several common species of harvester ants found in the United States:

- Florida Harvester Ant, Pogonomyrmex badius. This is the only eastern species and is found from Lousiana to North Carolina. The species tends to nest in open woodlands and grassy fields. The adults are dark rust red color.

- Red Harvester Ant, Pogonomyrmex barbatus. Wildermuth and Davis(1931) paid special attention to the red harvester ant since it is an important pest in agricultural regions. These ants make circular, bare areas, 25 to 35 feet across and are especially injurious in alfalfa and grain fields. They are known also to destroy trees in citrus orchards. According to these workers, the red harvester ant "is also a great annoyance around dooryards and is especially troublesome when in city lawns. In such localities, the ant is a nuisance not only because of its harvesting activities, but also because it has the unpleasant habit of inflicting painful stings, as almost all residents of a district where this ant occurs can testify."

- Western Harvester Ant, Pogonomyrmex occidentalis. This red ant may reach up to 3/8 inch/ 10 mm in length and is found at higher altitudes in most of the western states as far north as Idaho and Wyoming. Fritz and Vickers (1942) found the western harvester ant to be responsible for considerable damage to highways in Kansas. The ants remove the soil-binding vegetation at the edge of the road and tunneled beneath the surface of the road, hereby abetting erosion and damage to the roads during periods of rainfall.

- California Harvester Ant, Pogonomyrmex californicus. The California harvester ant is light red with somewhat lighter legs, and is about 1/4 inch/ 6 mm long; the thorax lacks spines. This insect is in the same category as Pogonomyrmex barbatus, for when it occurs immediately in the vicinity of the home, children and small animals playing thereabouts may be stung. Herms (1939) states: "These ants will readily attack humans and smaller animals. Hog raisers in the Imperial Valley, California, report many young pigs are killed by ants, particularly by the stings of P. californicus. It is a matter of common observation to see a small pig walk leisurely upon an ant mound and suddenly begin to kick and squeal, due to the terrific attack of the myriads of ants rushing forth from the nest. The animals commonly topple over with the legs outstretched and death may result."

These are the ants of the warmer and drier regions of the South and West, famous for their habit of collecting seeds and their vicious stings. Though never observed to invade the home, they nest in the lawn, around doorsteps, paths, etc. Entomologists are primarily interested in harvesting ants because of their habit of clearing large areas of cultivated fields, orchards and range land.