622 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
Superramitry FORMICOIDEA 
Famiry FORMICIDAE 
THE ANTS 
The ants are generally considered to constitute a single very large 
family, the Formicidae. They are among the most common and widely 
distributed of insects, occurring under “almost all conditions, and in 
number of individuals they probably outnumber all other terrestrial 
animals. They are easily recognized by the form of the abdominal 
petiole which bears one or two scales or nodes which are known, 
respectively, as the petiole and postpetiole. All ants are social, and, 
except for a few slave-making and inquilinous forms, have a well- 
differentiated worker caste of modified females, males, and females or 
queens. 
Their nests, or formicaries, present extreme variation in architecture. 
The number of ants in a fully developed colony may range from only 
a few dozen individuals in some species to hundreds of thousands in 
others. Their feeding habits differ greatly. The adults of some are 
strictly carnivorous, feeding on insects and other small animals; others 
are largely vegetarian, feeding on plants and seeds; whereas others 
feed on honeydew, fungi, fruit, and other substances. Although most 
species of ants nest in the soil, there are many that build their nests 
in wood, in timbers, in the trunks of decaying trees, or under the bark. 
Considering their abundance , they are not especially destructive to our 
forests. A few species cause considerable damage, but some are dis- 
tinctly beneficial predators on harmful insects. 
Large black ants belonging to the genus Camponotus are called car- 
penter ants, because of their habit of tunneling into wood. They 
attack cut timber, decayed or partially decayed trees, and even some 
living trees. The most common American species, the black carpen- 
ter ant (Camponotus herculeanus pennsylvanicus (DeG.)) (fig. 191) 
was well treated by Graham (794). ‘These are large black ants, some- 
times 14 inch or more in length. They build their nests in a great 
variety of places. They may attack the dead heartwood of living 
trees, logs, house timbers, or almost any wood materials. They do 
their oreatest damage in house timbers, poles, and standing trees with 
soft wood (fig. 192). In northern white cedar, Thuja occidentalis, 
Injury is very common, and in certain locations at least 20 percent of 
the trees that are cut show ant injury. On infested trees grown on 
swampy ground there is a loss of about 3 feet from the butt, and the 
loss on trees on higher ground may be 6 feet. Balsam fir, Abies 
balsamea, i the northeast is also ser iously damaged. The ants do not 
use the excavated wood for food, but they make galleries to form a 
home for the colony. They are rather ‘general “feeders, acting as 
predators on certain cater pillars and also obtaining honeydew from 
aphids. Their life history is similar to that of most ants. 
Mating takes place early in the summer, during what is termed 
“the nuptial flight.” The impregnated female may be taken into an 
old nest to replace an old queen or she may seek out a new place to 
form a colony. Once the new homie site is selected, she divests herself 
