many of their enemies, they encourage the development of heavy infestations that 
are capable of causing serious damage to affected plants. They also remove seeds 
from seed beds and feed on the sap or fruit juices from various trees and plants. 
Argentine ants are more or less uniformly light brown or brown, the antennae are 
12-segmented and without a club, and the petiole scale is well developed and 
inclined. Workers are from 2.2 to 2.6 mm long; when freshly crushed, they emit a 
stale, greasy, musty odor. Nests occur in many kinds of places, such as in the soil, 
in rotten wood, in cavities in trees, in refuse piles, and in bird nests and beehives. 
The number of ants present in well-established infested areas is beyond comprehen- 
sion. Fortunately, they are usually of minor importance as pests in forested areas. 
Iridomyrmex pruinosus (Roger) occurs throughout the Eastern and Southern 
States north to New York and Wisconsin. It nests in the ground and under the bark 
of logs and stumps, and is sometimes a nuisance in houses. The odor of freshly 
crushed workers resembles that of rotten coconut. 
The genus Solenopsis is represented by eight species in the United States, seven 
of which occur in the Southeastern States. They are commonly called fire ants. 
Nests are usually constructed in the soil, but also sometimes in rotten wood and in 
houses. The workers are aggressive and practically omnivorous. 
The primary diet of fire ants is insects, spiders, myriapods, earthworms, and 
other small invertebrates. They also may feed on plants, particularly seedlings or 
germinating seeds. Other economically important problems created by the imported 
fire ants are stinging of livestock, damage to farm machinery that strike mounds, 
loss of hay and grazing area, refusal of workers to enter heavily infested fields to 
cultivate or harvest crops, and hazards to human health from stings that may cause 
systemic reactions or complications from secondary infections (749). 
Both the red imported fire ant, Solenopsis invicta Buren, and the black 
imported fire ant, S. richteri Forel, were introduced from South America into the 
United States at Mobile, Ala.—the former, about 1940 and the latter, about 1918. 
S. richteri is more or less stable in a relatively small area in northeastern Mis- 
sissippi and northwestern Alabama. S. invicta is more widespread and is now found 
in nine States from the Carolinas to Texas. It is still spreading in all directions 
although the northward spread is slow (749). The two species are often very 
difficult to distinguish on the basis of color alone. Detailed examination of mor- 
phological characters such as the shapes of the head, thorax, and postpetiole is 
needed to separate these species (/72). 
Imported fire ant mounds are found in almost all kinds of soil, but most 
commonly in open areas. Few if any are ever found in heavily timbered areas, 
especially in hardwood stands. An average mound is about 30 cm high and 60 cm 
across; some are up to 90 cm tall. The larger ones are usually dome-shaped or 
conical, and may contain more than 100,000 ants. In heavily infested areas there 
may be more than 30 nests per hectare. Nests are also found in rotting logs, around 
tree trunks, and occasionally under buildings. The biologies of these species have 
been discussed (50/). Comprehensive treatments of ants may be found in the 
literature (265, 1109, 1282). 
Superfamily Vespoidea 
. This superfamily comprises two families, the Vespidae and the Pompilidae. 
Many species are social in habit and live together in colonies; others are solitary 
and live alone. The adults generally feed on nectar, sap, honeydew, or similar 
materials, whereas the larvae feed on other insects or spiders provided by the adult 
female. The larvae of some species feed on pollen and nectar. A few species are of 
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