6 the COLORADO EXPERIMENT STATION 
reported upon apple trees in England. Harris, in his “Insect In- 
,juries to Vegetation,’’ states that the louse had been known in 
France several years earlier than this. In i8oi it was reported 
in Germany by Hausmann, who described it and gave it its scien¬ 
tific name. In i8io it had become so abundant in Gloucestershire, 
England, that the farmers feared they would have to stop making 
apple cider, and it is still a serious pest there. In England it was 
early believed that this insect was first introduced upon nursery 
stock from America. Buckton, an English writer, in his “Mono¬ 
graph of British Aphidides,” seems to believe that this louse is a 
native of America, and states that it has been known to occur upon 
the American crabapple ;* but the first record we have of the oc¬ 
currence of the wooll}^ aphis in the United States is in Harris’ “In¬ 
sects Injurious to Vegetation,” published in 1841, more than a half- 
century after it had become a recognized pest in Europe. 
In England, before the real cause of the mouldy appearing 
trees had been discovered, this malady was called American blight. 
On account of the blood red stain, caused when this louse is 
crushed, the Germans have called it the blood-louse. But wher¬ 
ever this insect may have its native home, and whatever may have 
been its native food plants, we know that it now occurs in practi¬ 
cally every apple-growing region on the globe and, as it is an 
insect of much economic importance in Colorado, we shall 
go rather fully into its habits, life history, and means of control. 
THE LOUSE DESCRIBED. 
Most orchardists will think a description unnecessary, and to 
them it would be were it not for the fact that there are many 
other woolly lice upon other plants that are frequently mistaken 
for the woolly aphis of the apple. 
The name woolly aphis was given because of the white se¬ 
cretion occurring so abundantly upon the wingless lice, and, to 
some extent, upon the winged ones also. This is not a woolly 
covering in the sense that it grows like wool or hair. It is really 
a fatty or waxy secretion similar to the shellac, China wax, or bees¬ 
wax of commerce. Small glands beneath the skin give off delicate 
white threads of this material through minute pores. This white 
secretion, when warmed, will melt like tallow. It is easily re¬ 
moved from the body, but in a short time the body will be cov¬ 
ered again. It serves as a protection to the louse against storms, 
and, to some extent, no doubt, from its insect enemies. 
* Buckton probably had in mlind the statement made by Pitch in his 
first N. Y. report, p. 5, in which he says he has seen the winged form of 
the woolly aphis numerous in groves where he suggests that It had come 
from the shad-bush (Aiiielancliier sp.). It is altogether probable that Fitch 
mistook the winged form of Pemi>higus corrugatiis Sirr. for winged migrants 
of the woolly aphis of the apple. 
