34 THE SAX JOSE OR CHINESE SCALE. 
drawn. Special topographical conditions and protecting mountains 
will probably account for other divergences. 
In the lower austral and tropical regions the San Jose scale, as 
pointed out by Doctor Howard, may not prove as injurious as in the 
upper austral, and this follows the general rule regarding armored 
scale insects in warm countries. Armored scales rarely appear or 
thrive in the moist Tropics, as shown by the explorations of the writer 
in the East and West Indies. Fungous diseases, which thrive in warm 
and moist climates, are the principal agency in keeping such scale 
insects in check, and in the case of the San Jose scale the common 
scale fungus Sphaerostilbe coccophila has already done good work in 
Florida and other portions of the lower austral zone. Moisture is a 
prerequisite in the case of this disease, and little benefit comes from 
it in the drier portions of this zone. Too much stress, however, should 
not be put on zonal limitations, and there may always be outbreaks 
of longer or shorter standing in the borders of the transition region. 
HABITS AND LIFE HISTORY. 
NATURE OF THE DAMAGE. 
The San Jose scale, as already stated, occurs on all parts of the 
plant— limbs (PL I; PI. VI, fig. 1)," leaves, and fruit (PL VI, fig. 2). 
As the plant becomes badly infested the scales lie very close together 
on the limbs, frequently overlapping, sometimes with several young 
ones clustering over the surface of an old mature scale. The gen- 
eral appearance which they present is of a grayish, very slightly 
roughened, scurfy deposit. The natural rich reddish color of the 
young limbs of peach, pear, and apple is quite obscured when these 
trees are thickly infested, and they have then every appearance of 
being coated with ashes. When the scales are crusht by scraping, 
a yellowish, oily liquid will appear, resulting from the mashing () f 
the soft, yellow insects beneath the scales. Examined under a hand 
lens during the summer, numbers of the little orange-colored larva 4 
will be seen running about, and the snowy white young scales will be 
interspersed with the old brown or blackened mature scales. The 
appearance presented at this time under the lens is shown in lig. 2. 
Very frequently the scale has a marked tendency to infest the extrem- 
ities of the branches and twigs. This is particularly noticeable with 
pear. As usually found on peach, the scale is massed often more 
densely on the older growth, and works out more slowly toward the 
new wood. 
The leaves are much less apt to bear scales, but in severe cases the 
upper surface pai ticularly becomes infested, the scales frequently rang- 
ing in two or more quite regular rows on either side of the midrib. 
