‘EXPERIMENTS ON ORANGE SCALE-INSECTS. 23 
of older branches and the trunk of the tree. They do not yield as 
readily as the other varieties, on account of their matting together; a 
little scratching with the Gna of a piece of palmetto root, a handful of 
moss, or any similar thing, will make it easy to wash them off, even 
with a spray-nozzle. 
I had ten feet of conducting hose replace the usual three feet on the 
engine, for the purpose of taking a solid stream up to wash off limbs 
thickly encrusted. This should form a portion of every equipment for 
this work. 
No positive knowledge of the value of any application to.scale insects 
can be obtained without the use of a microscope. This instrument en- 
ables the observer to quickly ascertain the effect produced. Experience 
has shown that too much dependence may be placed on the microscope, 
and false results obtained ; as, for instance, samples taken from differ- 
ent parts of a tree will often show avery different result in percentages. 
If samples be not taken for each examination from the same places, the 
result may be misleading. Again, the scales are not alike in adhesive- 
ness ; some loosen more readily than others after the application of an 
effective solution, and many of these will be blown or washed off; per- 
centages of the remainder will not fairly show the effects; whilst if the 
weather be calm and no raiu falls, the results may be considered fair and 
reliable. 
By reference to numbers 2, 3, 4, and 5 it will be seen that the imme- 
diate results are well indicated by the microscope; whilst from 8 to 
17, inclusive, the results appear to be very irregular, showing no pro- 
portionate result to strength of solutionused. This arises in great part 
from scales blown off 8 to 17 by a very strong wind, the application be- 
ing made immediately after a storm. The scales had been loosened by 
the storm in different degrees, according to exposure, and the immediate 
results were greater as the exposure to the storm, and afterwards to the 
wind, was greater. The storm spoken of lasted for thirty hours, the 
wind blowing a gale, the rain falling in torrents. The wind continued 
to blow very hard for one day after the rain ceased. 
Many of the worst infested trees, most exposed to the storm, showed, 
after its cessation, clean bark on the storm side, the scales being blown 
or washed off, and on the side away from the storm they were much 
more loose than usual. After a few days they became much more ad- 
herent than usual. 
Solutions of murvite were applied to these exposed trees the day 
after the storm, and in two days the scales thus treated were nearly all 
gone. 
Repeated experiments with solutions of various strengths prove that 
several parasites are unhurt by solutions which destroy the scale insects; 
and it is generally the case that in the examination with the microscope, 
after the application of murvite solutions, large numbers of parasites are 
present and very active. In specimens 21 to 28 there may be cause to 
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