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Insects Injurious to the Mango. 15 
found at almost any time of the year. The activities of the scales, 
however, are much retarded during the winter when the foliage of 
the mango is dormant. During winter more adult scales are present 
in proportion to the young. This no doubt is due to the lack of 
young foliage and the lower temperature. The adults reproduce al- 
most continuously on the mango in Florida, and the generations over- 
lap considerably, so that at any time the scales may be found in all 
stages of development. 
The young, or “crawlers.”—During the latter part of February or 
the first part of March, as the new growth commences on the mango, 
the “crawlers” appear in great numbers. These are born beneath 
the adult scales on the older leaves, and as their natural instinct is 
to seek the newer growth of foliage, great numbers of these small 
crawlers may be seen traveling toward the newer foliage along the 
twigs. In due time in the spring, the mango, like the avocado, 
sheds its older leaves and with them many scales, but a sufficient 
number has gained foothold on the newer growth to perpetuate the 
species on the tree and to continue the infestation. As with other 
scales of a like nature, the young are tiny, oval in shape, provided 
with antenne, six legs, and threadlike mouth parts. After wander- 
ing about for a short while, the young scale settles down, thrusts 
its threadlike mouth parts into the tissues of the leaf, and begins the 
extraction of the sap, upon which it feeds. With the first 
molt the crawlers lose their antennze and legs. As the scale 
grows, the cast skins are thrust aside for a new and larger covering. 
Crawlers which were placed on leaves February 2, 1918, became 
adult scales May 20, 1918, showing that at this time of year ap- 
proximately 3} months are required to go through a generation. 
From the writer’s observations approximately three generations are 
produced on the mango in southern Florida. During the latter part 
of June and early July great numbers of the crawlers are in evi- 
dence. The generations overlap greatly, however, and there is no 
distinct demarkation showing when one generation ends and an- 
other begins. 
In Florida, the writer has taken this species on the rose apple, 
custard apple, sapodilla, mango, and Allamanda. In the West 
Indies it has been recorded on mango, breadfruit, Jasminum, Ixora, 
sapodilla, Allamanda, star plum, star apple, nutmeg, and custard 
apple. 
CONTROL. 
The best time to control this scale on the mango is when the trees 
are dormant, as from the middle of December until the first of Feb- 
ruary. Oil emulsions have been found satisfactory. There are a 
number of oil emulsions on the market, some of which when applied 
to the waters used in spraying in southern Florida work very satis- 
