Ill 
much liquid is needed to the tree. On the other hand, the scales are 
now larger and firmer and more resistant to the insecticide than in 
summer. 
The extensive operations against this scale by the Superintend- 
ent of Lincoln Park during the winter of 1905-06 were followed by 
one of my assistants, Mr. E. O. G. Kelly, sent repeatedly to Chicago 
for this purpose. Nearly every tree and shrub in this park infested 
by the maple scale was sprayed under the immediate supervision of 
Mr. R. W. Braucher. Two thousand six hundred and seventy-three 
trees and 4456 shrubs were sprayed, nearly half the trees ranging 
from large to very large, and the remainder from small to medium. 
The materials used in this treatment were 4153 gallons of kerosene 
and 3074 pounds of soap, made up in 20,800 gallons of kerosene 
emulsion. The cost of the latter was approximately 2 cents a gallon. 
With the outfit used, a Fairbanks-Morse power sprayer with double 
"Vermorel" nozzles, it required, on an average, five minutes to spray 
each tree, or an hour for twelve trees. Eight men were employed 
with the outfit, making an average service of forty minutes of one 
man's time per tree. Six and seven tenths gallons of emulsion were 
applied to the average tree, at a total cost of 43 cents for both ma- 
terials and labor. 
In spraying operations, ladders and long canes were used in or- 
der that all parts of the larger trees might be reached by the spray. 
In the greater part of the work 19 and 20 per cent, emulsions of 
kerosene were applied. To make this up in 200-gallon lots, 20 gal- 
lons of water and 27 to 30 pounds of "Tak-a-nap" soap were placed 
in the mixing tub. and steam was introduced until the soap was dis- 
solved and the solution was boiling hot. Forty gallons of kerosene 
were then slowly pumped into the tub, and the mixture was pumped 
back into itself until the kerosene no longer rose to the surface when 
the pumping ceased. The emulsion was finally diluted by adding 
hot water to make 200 gallons. 
A part of the trees examined were sprayed between December 
26 and January 5, and others January 11 and 13 and March 30. 
The effects of the spray were determined by comparing ratios of 
dead and living scales on trees which had been treated, with those 
from others examined at the same time which had received no 
treatment. A determination of the condition of the scales subse- 
quent to treatment was a much more difficult matter at this season 
than during the summer. The dormant insects themselves were 
comparatively large and dense, and changes due to death were pro- 
duced but slowly in the cold midwinter weather. From twenty- 
