A FEW ORCHARD PEANT DICE . 13 
middle of August. We had an excellent illustration of what the 
predaceous insects can do in this way last year. Probably this in¬ 
sect never was so abundant in the orchards of the state as they 
were last year, from their first appearance in the spring until 
about the middle of July. About that time the enemies had become 
so abundant that a noticeable decrease soon became apparent and 
by the loth of August it was almost impossible to find a living 
louse above ground. Upon the roots there was no noticeable 
change in the infestation. The enemies then left the trees, and 
the few lice that were overlooked, with a few others that migrated 
upward from the roots, soon began to increase in numbers, so that 
by the last of September the trees were showing a light infestation 
again. Apparently this is all easily explained. The winter of 1906- 
7 was very open and mild, so that plant lice of all kinds lived 
through unusually well and were very abundant early in the spring. 
As a result, there was a very abundant food supply for their 
enemies, which also increased with great rapidity, so that by the 
first of August they began to get the upper hand of the lice, and 
to prevent their own starvation, almost completely ate the latter 
from every exposed place. In the Grand Valley the greater por¬ 
tion of this benefit was done by the lace-winged fly (Plate I, Fig. 
15), while upon the Eastern slope the lady-bettles (Plate II, Figs. 
12, 13, 14, 15) were the chief benefactors, with the lace-winged 
flies and the Syrphus flies as efficient helpers in the good work. 
Specimens of a small black parasitic fly* were taken by Mr. L. C. 
Bragg, ovipositing in this louse at Fort Collins, August 20, 1908. 
remedies above ground. 
Wherever this louse can be reached by sprays, it may be de¬ 
stroyed, like any other plant louse, but one important precaution is 
necessary, the spray must be applied with sufficient force to wet 
through or remove the woolly covering. This louse is then more 
easily killed than is the green apple aphis, which curls the leaves 
for protection. 
There are several spray materials that may be used with suc¬ 
cess. In fact, any spray that is generally successful when used 
for the destruction of plant lice may be considered useful for the 
destruction of this insect. 
kerosene emulsion. 
When properly made, a good kerosene emulsion has no supe¬ 
rior, as a spray for the destruction of the woolly aphis, so far as 
we have been able to determine, and it penetrates the woolly cov¬ 
ering better than most insecticides. When used in the usual strength 
of I-1 5 (7 per cent.) oil we have always found it to be suffi- 
*Aplielinus mail (Hald.), determined for us 'by Dr. L. O. Howard. 
