TWO DESTRUCTIVE ANTS. 5 



DISTRIBUTION. 



The agricultural ant occurs from the Brazos Kiver westward. 

 West of San Antonio it is replaced by closel}' allied forms. Farther 

 north, in Kansas and Nebraska, a distinct species {P. occidentalis 

 Cress.) occurs. The agi'icultural ant is conspicuously a resident of 

 open places and does not occur in wooded localities. 



HABITS. 



This ant sAvarms early in the season, generally after a rain. At 

 such times the males and females come out of the nest in great num- 

 bers, covering the ground for many feet. Mating takes place at this 

 time, after which the females fly away. When they alight their 

 wings are cast and they begin to dig a cell for a new colony. The 

 males after mating are driven away by the workers or killed if they 

 persist in returning to the nest. At the time of this SAvarming multi- 

 tudes of the ants are destroyed by birds and horned lizards. 



Many years ago it was announced that the agricultural ant actu- 

 ally plants certain grasses in order to obtain quantities of seed to use 

 in provisioning the nests. In fact, it was on this supposition that 

 one of the common names which have come into use was given it. 

 Upon careful investigation, however, it was found that the ant does 

 not plant seed intentionally, although it undoubtedly does so acci- 

 dentally. The facts were brought out by Prof. W. M. A^Hieeler. The 

 seeds of several species of grass and common weeds are taken into 

 the nests. AMien the moisture is too great in the nest some of these 

 seeds sprout and thus become unsuitable for food. Under such cir- 

 cumstances the ants carry out the sprouted seeds and deposit them in 

 the immediate vicinity of the nest where many take root and groAv. 

 Of course, this can not be considered intentional planting of the 

 seeds, because the ants deal with the S])routed grain exactly as they 

 would Avith any substance that Avas unsuitable in their nests; that is, 

 they simply carry it out and throAv it aAvay. 



DAMAGE. 



The economic importance of the agricultural ant is due to the fact 

 that it Avill not alloAv A'egetation to groAv in the immediate vicinity 

 of its nest and to its powerful sting Avhich it uses on the slightest 

 provocation. If the colonies happen to be in fields such as alfalfa, 

 corn, or cotton, the area of loss nuiy amount to considerable, and the 

 same is true to a certain degree of pasture and range lands. More- 

 oA'er, in fields which are moAved the mounds interfere Avith the Avork- 

 ing of the machine, and the ants are likely to attack the horses. 

 There is some degree of compensation for the loss of the land cleared 

 by the ants. It Avill be noted that in a circle just outside of the area 



