RELATIONS WITH OTHER ARTHROPODA. 65 
During a period of 18 months 48 species of scale insects have been 
collected in Audubon Park, New Orleans, all of which are attended 
by the Argentine ant. Many of these species, however, are visited 
sparingly, and are evidently regarded as sources of food when the 
more popular species fail to furnish a sufficient amount for the needs 
of the ants. A few species are particularly favored by the ants, and 
the trees and plants upon which they occur are always crowded with 
large numbers of the workers. 
Among these favored species may be mentioned the Magnolia scale 
(Neolecanium cornuparvum Thro), which is found upon the various 
magnolia trees. This scale is very large and unarmored, and the 
young scales appear in great numbers during February and March. 
As this is the period during which the ants have the greatest difficulty 
in securing sufficient food it naturally follows that they concentrate 
upon the magnolia trees in immense numbers, and the soil at the 
bases of the trees is turned into gigantic ant nests. During June and 
July this scale is brought under control by the larva of a small black 
ladybeetle, and the number of ants in the magnolia trees falls off 
greatly. By this time, however, an abundance of scale insects and 
plant lice of many different species can be found everywhere, and the 
ants do not have to place such dependence upon the magnolia scale. 
Another species which attracts great numbers of workers is the soft 
scale (Coccus Jiesperidum L.) . This species has been collected upon 
a variety of plants in Audubon Park, among which may be mentioned 
the orange, banana, Camellia japonica, coral tree, cocoa tree, rubber 
trees, myrtle, and maidenhair ferns. This scale can be found in all 
stages at almost any time of the year, and is always heavily attended 
by ants. 
Other important scale insects from the Argentine ant's point of 
view are the sugar-cane mealy-bug (Pseudococcus calceolaria Mask.) , 
the two barnacle scales (Ceroplastes cirripediformis Comst. and 
C.floridensis Comst.) , and the black scale (Saissetia olese Bern.) . The 
last three species are found upon a variety of plants. 
A complete list of the scale insects and aphides which this ant 
attends would comprise a check list of these species for the entire 
ant-infested territory. The following list, however, includes the 
more important species upon various plants and crops which are the 
most eagerly sought after by the ants. Most of the determinations 
have been made at Washington, D. C, through the courtesy of 
Messrs. E. R. Sasscer, J. G. Sanders, and Theo. Pergande. So far as 
possible the species most attractive to the ants have been placed 
nearest the host plants, and they follow in order of preference within 
certain limits. 
75508°— Bull. 122—13 5 
