New YorK AGRICULTURAL EXPERIMENT STATION. 423 
tions of their bodies through the crust, but few young were 
born, and these were apparently unable to establish themselves, 
Conclusion.—In the tests, conducted under ordinary field 
conditions, the insoluble sediment has shown very weak insecti- 
cidal properties. Thorough applications of it have never ma- 
terially checked the breeding of the San José scale, and conse- 
quently have afforded very little, if any, protection to the trees. 
As has generally been believed, the experiments have shown 
very conclusively that, as regards this insect, the lime-sulphur 
wash derives its chief insecticidal value from the soluble lime- 
sulphur compounds. In purchasing preparations for scale 
treatment, the presence of sediment in appreciable quantities 
in a commercial lime-sulphur mixture is undesirable for two 
reasons,—(1) because of its cost, and (2) because of the dan- 
ger of uncertain results in spraying, through the substitution 
of insoluble materials for the clear solution. 
Judging from the results of these experiments it would ap- 
pear that there is no objection to adding the sediment, or 
sludge, of a commercial or a home-made lime-sulphur wash to a 
clear solution as extra material, to give body to the prepara- 
tions. The actuai value derived from their addition is not 
known. <A _ heavy coating on the trees serves to indicate the 
thoroughness of the spraying, and according to its thickness 
and adhesive properties exerts certain smothering effects on 
such sluggish insects as scales and lice. On weathering off, 
the flakes of the insoluble materials also carry with them some 
of the protective coverings of the scales, and perhaps a few of 
the insects themselves. 
STRENGTHS OF EFFECTIVE MIXTURES FOR SCALE 
AND BLISTER-MITE. 
In the use of the commercial lime-sulphur solutions there 
has been quite a little uncertainty as to the range of dilution 
with water, to obtain:mixtures of suitable killing properties. 
The proportions that have usually been recommended for dor- 
mant treatment in advertising circulars would appear, on the 
basis on the sulphur content, to make a weaker spray than the 
