4 FARMERS' BULLETIN. 928. 



ing resowing and protection of the seed. The ant also has been a 

 pest at times in greenhouses, where it occasionally cuts into certain 

 flowers and fosters mealybugs and aphicls. 



The general belief has been that in Louisiana the ant caused far 

 more serious damage to the orange trees than to any other crop. It 

 was thought to bring about a tremendous increase of all orange- 

 infesting scales, white flies, and aphids, to destroy the blossoms and 

 branches, injure the roots, greatly reduce the crop, and even kill the 

 trees. In reality the ant is responsible for only one form of direct 

 injury to orange trees. Rarely it chews into the petals and stamens 

 of open orange blossoms for the purpose of squeezing out the sap. 

 This occurs only on isolated trees, where food is scarce in compari- 

 son with the number of ants, and the amount of injury resulting, is 

 unimportant except on rare occasions. The ants habitually visit 

 orange and other flowers to obtain nectar and to capture flower- 

 feeding insects, but ordinarily do no damage to the flowers. The 

 ant does not and can not injure sound oranges, although it enters 

 and feeds upon the juice of broken ripe or rotting fruits. 



The chief importance of the Argentine ant in orange groves is due 

 to the fact that certain injurious scale insects become much more 

 abundant as a result of its presence, and that it fosters mealybugs and 

 aphids. 



HOW THE PRESENCE OF THE ARGENTINE ANT FAVORS IN- 

 CREASED INFESTATION BY SCALE INSECTS. 



Two very distinct groups, or classes, of scale insects infest orange 

 trees: (1) The armored scales, or those which settle permanently in a 

 particular spot, lose their legs, and form a protective covering, such 

 as a scale or shell, over the body. The eggs are deposited and the 

 young hatch under the protection of this shell. The hard, flattened, 

 apparently lifeless particles encrusting the branches and trunk and 

 sometimes the fruit and leaves of orange trees are the armored scales. 

 (2) The unarmored, or soft scales. These do not form a shell or 

 scale over the body nor do they lose entirely their legs and the power 

 of changing location. They are usually less flattened, softer, and, 

 when mature, in most cases larger than the armored scales. Certain 

 kinds, such as the mealybugs and the fluted scale, move about from 

 one location to another throughout their lives. Others, such as the 

 black, soft brown, and wax scales, usually settle down when partly 

 grown and remain in one spot, though they are able to move about 

 even in the later stages. The males of both classes of scale insects are 

 minute gnatlike insects with wings. 



The relations of the Argentine ant with the soft scales and aphids 

 are direct and mutually beneficial. The ant is attracted to these 

 insects for their honeydew, a sweet liquid which it induces them to 



