well established and of some size. Where this insect is abundant all 
the roots of a young tree to the depth of a foot or so become clubbed 
and knotted by the growth of hard fibrous enlargements, with the results 
in a year or two of the dying of the rootlets and their ultimate decompo- 
sition with attendant disappearance of the galls and also of the lice, so 
that after this stage is reached the cause of the injury is often obscure. 
On the trunks the presence of the lice sometimes results in the rough- 
ening of the bark or a granulated condition which is particularly notice- 
able about the collar and at the forks of branches or on the fresh 
growth around the scars caused by pruning, which latter is a favorite 
location. On the water shoots, they collect particularly in the axils of 
the leaves, often eventually causing them to fall, and on the tender 
greener side of the stems. The damage above ground, though com- 
monly insignificant, is useful as an indication of the probable existence 
of the lice on the roots. <A badly attacked tree assumes a sickly appear- 
ance and does not make satisfactory growth, and the leaves become dull 
and yellowish, and even if not killed outright it is so weakened that it 
becomes especially subject to the attacks of borers and other insect 
enemies. Injuries from the woolly aphis are almost altogether confined 
to the apple, even the wild crab not being so liable to attack or at least 
injury by it. There is, however, some difference exhibited by different 
varieties of apple in immunity, and particularly is the Northern Spy 
proof against it, and it is possible that, as in the case of the grape phyl- 
loxera, by employing root stock from seedlings of the more resistant 
varieties or-from wild crabs, considerable protection would result. The 
character of the soil also exerts some influence—that is, loose dry soils 
are favorable and wet compact ones are unfavorable to the aphis. 
ORIGIN AND DISTRIBUTION. 
There is considerable difference of opinion as to the origin of the 
woolly louse of the apple. The belief has fluctuated between a Euro- 
pean and an American origin for this insect, but the weight of evidence 
seems to indicate the latter. At any rate, it is an insect which is most 
readily carried from “place to place with nursery stock of the apple, and 
it has been so transported to practically all the important countries of 
the world which have been reached by colonization or European settle- 
ment. The woolly aphis was first noticed in England in 1787, on some 
stock imported that year from America, and was early called the Ameri- 
can blight. Hausmann described it in 1801 as infesting apple trees 
in Germany, and within the next twenty-five years it was recognized as 
a serious enemy of this fruit tree throughout England, Belgium, north 
France, and Germany, but seems never to have been especially notable 
in the warmer latitudes of Europe. 
It was very early introduced into Australia and New Zealand, and is 
