THE SAN JOSE SCALE. 2a 
most, and they crawl with considerable rapidity and great persist- 
ence, so that they might possible descend from one tree and crawl 
for a number of yards to another; but the spread in this manner is 
insignificant. Where trees are close together they may pass from 
the branches of one to the branches of another. They rarely crawl 
long in one direction, however, but rather move rapidly around, 
irregularly and at random. Usually they do not go farther than is 
necessary to find a good place to settle and at once begin to form 
ascale. This very interesting process is shown in figure 2. Assoon 
as the young louse has inserted its beak into the plant, and has 
begun to feed, a change comes over it, and within a few hours it is 
entirely covered with a fine, white, waxy film. This turns to yellow 
and then gray or even black, and the creature is a fixture, absolutely 
incapable thereafter of shifting its position under any possible 
circumstances. Strong winds may carry the young bodily from 
one tree to another, but the principle method of spread is by means 
of other insects which are winged and by birds. The active young 
lice will soon crawl upon any small winged insect, particularly if 
the latter is of a dark color, and they may be carried by it to a con- 
siderable distance. They also crawl upon the feet of birds which 
visit the trees and may thus be carried for miles. They are often 
found upon ants, and ants, as every one knows,are great travellers. 
The difficulty in moving from one place to another, and the depend- 
ence upon external agency for their distribution, will account for 
the fact that trees here and there in an orchard newly set out may 
be very badly infested, while not atrace will be seen on the trees on 
either side. Few birds or insects visit a young orchard thatis at 
all well kept, and the distance between the trees, especially if the 
landis cultivated,is altogether too great to be covered by the young 
lice, even did they know enough to make a bee line for the nearest 
point. The result is that everything fixes upon the tree upon which 
# was hatched, killing it more rapidly than would otherwise be the 
case, butat all events confining and preventing its spread to points 
not before infested. This also explains why nursery stock is so 
evenly troubled: here the trees are grown just as closely together 
as is possible in rows, and there is no hindrance tocrawling from 
one to the other. 
As the insects must feed for a time in the spring before attaining 
their full growth, it follows that oniy such as are fixed to the tree 
itself have any chance of reproducing their kind. Those that fix to 
the leaves fall with them, and as these dry or decay the insect dies 
for want of food before attaining maturity. Those on the fruit are 
removed when this is ripe. We have thus to consider only the 
wood, free of all leaves and fruit, when attempting the destruction 
of the insect. 
All our deciduous fruit trees and many forest trees are attacked 
by this insect in varying degrees. Smaller plants, like currants, 
gooseberries, raspberries, roses, etc.,are also to its taste. In fact, 
nearly all bushes and trees will support it. 
Like most other insects this scale insect hasa number of parasites 
thatkillsomeofthem. Large numbers arealso eaten by suchinsects 
