26 
THE COLORADO EXPERIMENT STATION 
wingless eemale oe summer generations 
Plate I, Fig. 3. 
The summer wingless females (all after the stem mother) 
when fully grown, are a trifle larger than the first generation, are 
yellowish green in color, have 7 joints to the antennae, both antennae 
and cornicles are longer than in the stem mother, and the cornicles, 
cauda and the greater portion of the antennae are black. These 
females continue until late fall and are very prolific, giving birth 
to living young. 
WINGED females 
Plate I, Fig. 5. 
The winged females also give birth to living young lice. They 
fly about to other trees and so establish many new colonies, some of 
which will be likely for a time to escape being found by their 
enemies. 
These winged migrants are not numerous until the third 
brood and they continue to appear in considerable numbers until 
about the last of August, when they soon disappear, and true sexual 
males and egg-laying females take their places. 
About the first of September* * males and egg-laying females 
begin to appear. The males and females pair and the latter begin 
to lay eggs about the middle of September and continue to do so 
until killed by severe freezes. 
males 
Plate I, Fig. 7. 
The male is wingless, is yellowish or rusty brown in color, and 
is much smaller than any other adult lice of the year. 
egg-laying female 
Plate I, Fig. 8. 
The egg-laying female is considerably larger than the male, 
but is smaller than the other female lice of the year and is yellowish 
green in general color with considerable variation. 
NATURAL ENEMIES 
This louse is attacked by about the same natural enemies as 
the wooll aphis. The Lady Beetles seem to us to be the most efficient 
as destroyers of it though the syrphus flies and aphis lions (lace¬ 
wing flies) also kill great numbers. They are almost never attacked 
by parasites, in fact the only parasitic attacks that we have seen have 
been by a minute Chalcid (Alphalinus mali)^ that causes the lice to 
change to a deep coal black while they retain their natural size and 
shape. 
* Our earliest date for males at Fort Collins is September 4. 
* Determined for me by Dr. L. O. Howard. 
