THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 35 
very scatteringly and, as a rule, was parasitized or had been de- 
stroyed by its natural enemies. This was true in orchards overrun 
by ants and in orchards free from ants, indicating, at least, that 
so far in southern California the helpful influence of the ant, if any, 
in relation to this scale insect has not overcome the effective control 
of the scale by its natural enemies. 
Aside from the well-known effectiveness of the Australian lady- 
beetle (Novius cardinalis Muls.), this control seems to be due, in 
Los Angeles County, chiefly to the parasitic fly Cryptochaetum mono- 
phlebi Skuse, aided, however, by hymenopterous parasites and the 
larvae of lacewing flies. 
INFLUENCE OF THE ANT ON ABUNDANCE OF THE BLACK SCALE IN LOUISIANA. 
As already stated, the black scale {Saissetia oleae Bern.) does not 
yet occur in the orange groves proper of Louisiana, and, Mierefore, 
as with the fluted scale, no extensive tree-banding experiments could 
be conducted in this State during the seasons 1913 to 1915 to deter- 
mine the effect of ant attendance on its abundance. 
The black scale occurred in moderate numbers on oleander in 
New Orleans, and from these trees was transferred and colonized 
on young orange trees and an experiment of this nature attempted. 
The progeny of the colonized scales made an equally good start on 
both ant-free and ant-invaded orange trees. Nevertheless, the scales 
failed to reach maturity in a single instance, even where constantly 
attended by ants, and although they decreased a trifle more slowly 
where attended than where not attended by ants, all scales had dis- 
appeared from both banded and nonbanded trees within six weeks 
from the starting of the experiment. 
INFLUENCE OF THE ANT ON ABUNDANCE OF THE BLACK SCALE IN CALIFOBNIA. 
The black scale has been rated as the most economically important 
of the citrus scales in California, 1 where it is generally controlled by 
fumigation. The observations on the relation of the ant to this scale 
were made in orchards in which fumigation had been temporarily 
neglected. In an experiment in which five scale-infested orange trees 
were banded to exclude ants in April, and a similar five left accessible 
to them, the amount of scale infestation remained practically equal 
on both sets of trees throughout the summer, from April to 
September. 
In other words, after excluding the ants from five of these trees 
for a period of nearly five months but little difference in the amount 
of black-scale infestation or in quantity of sooty mold could be de- 
tected between them and five similar trees very heavily invaded by 
iQuayle, H. J., op. cit., p. 445. 
