24 the coeorado experiment station 
while Rome Beauty, Black Twig, Ben Davis and a few others are 
close seconds, and the Northern Spy is scarcely attacked at all. 
This insect gets its food by inserting its beak and sucking 
the sap from either the leaves or the rapidly growing, softer and 
more tender twigs. For this reason rapidly growing young trees, 
grarts, and water sprouts are worst infested. When upon the fo¬ 
liage, this louse feeds, for the most part, upon the under side of the 
leaves, which curl in such a way as to give it considerable protection 
from the direct rays of the sun, and from sprays that are not used 
with force and thoroughness. 
LIEE HISTORY 
Bike most insects, this green aphis has very definite life habits. 
Probably we cannot do better than to begin with the egg and fol¬ 
low it through its different stages of development. 
THE EGGS 
» 
The winter is past entirely in the egg stage upon the twigs of 
the trees that were infested the previous fall. 
Many lice select the axils of buds and rough places in the 
bark for the deposition of their eggs, but this one seems to prefer 
the free surface of the rapidly growing shoots. When the lice 
are abundant, the water sprouts, in particular, are often fairly 
blackened with eggs (see Plate III, Figure 5). 
When first deposited, the eggs are light green in color, but 
soon become shining black from the action of the sunlight upon 
them. They are long oval in shape and are just large enough to 
be plainly seen by one who has good eye sight. By actual measure¬ 
ment it would require 40 of these eggs, placed end to end, to ex¬ 
tend one inch. 
Very few of the eggs ever hatch, according to our observations. 
On the eastern slope, at least, it seems doubtful if more than one 
per cent hatch in average years. Even this small percentage of the 
eggs hatching is sufficient with the rapid rate of increase to enable 
this insect to become destructively abundant before fall. When the 
time arrives for the little louse to come from its winter quarters, 
the shell splits longitudinally upon the upper surface near one end 
and the prisoner, with much writhing and kicking works itself 
out. No definite date can be fixed for the hatching. The first 
lice were found emerging.in 1907 at Palisades just as the first 
apricot blossoms were opening. At that time the apple blossoms 
were but little swollen. In a general way it may be said that the 
lice begin to hatch a little before the apple buds show any green and 
continue to hatch for two or three weeks, depending upon whether 
the weather is warm or cold most of the time. 
