10 
given a full account of this new discovery in the report which follows, it will be need- 
less to more than call your attention to it in this place. * 
As heretofore, I am indebted to yourself for suggestions and other help. 
Respectfully, yours, 
D. W. COQUILLETT. 
Protec. (VV .RIEE Y: 
U. S. Entomologist. 
RESIN SOAPS AND COMPOUNDS FOR THE DESTRUCTION OF THE RED 
SCALE. 
Karly in July of the present year I received a letter from Mr. L. O. 
Howard, acting entomologist during the absence of Professor Riley, 
instructing me to obtain permission from some person owning a number 
of large-sized orange trees which were thickly infested with the Red 
Seale (Aspidiotus aurantii Maskell), and then have the trees sprayed 
with one of the most approved resin sprays obtainable, the spraying 
to be repeated as often as would be found necessary in order to prac- 
tically free the trees of these pests, or at least to prevent them from 
becoming so numerous as tointerfere with the healthy growth of the 
trees, the object sought tor being to demonstrate that citrus trees badly 
infested with these pests can be cleaned and kept in a healthy, grow- 
ing condition by the use of the resin spray. 
Before entering upon this work I concluded to make a series of pre- 
liminary tests with various preparations, containing resin and other in- 
gredients in varying proportions, with a view of ascertaining the best 
and most desirable preparation to use in my field work referred to 
above. Accordingly I went down to Orange, in the adjoining county, 
which bears the same name, and, on the 17th, 18th, and 19th of July, 
made fourteen tests with various preparations, repeating one of these 
and making several additional tests on the 7th and 8th of the following 
month. The one giving the best results was used a trifle too strong, 
as I subsequently ascertained that it produced a discoloration on the 
underside of some of the oranges, or where they came in contact with 
each other or with a leaf or branch. For this reason a slightly weaker 
solution would produce better results, and doubtless the following pro- 
portions will be found the most effectual to use during the hotter part 
of the year: 
PROMS ae Sogo ccan eaes Tee EEE ete eee eee pounds.. 18 
Caustic soda (70 per cent. strength) ........-.....--... do:2-2 440 
Mish: O12 tie ocsaslatnane ee eens oes ee eee ee eee pints... 24 
Watermovmalke =a. 2205 Se see ees tee ee ee ee gallons.. 100 
The necessary ingredients are placed in the boiler and a sufficient 
quantity of cold water added to cover them; they are then boiled until 
dissolved, being occasionally stirred in the mean time, and after the 
*This portion of Mr. Coquillett’s report has been published in advance in INSECT 
Lire, Vol. II, double No. 6 and 7 (January and February 1890),—c. v. R. 
