34 BULLETIN NO I, DIVISION OF ENTOMOLOGY. 
day the scales were loose, and a week afterward the limbs were free and 
clean. Many of the leaves dropped. 
2. Five large twenty-year-old trees having Mytilaspis ; dilutions, rosin 
soap ; 30 gallons used ; clean within a week ; lost most of their leaves. 
3. Five hundred small trees, 2 to 4 feet high, affected with the Lecan- 
ium ; used 100 gallons dilution b, whale-oil ; scale dead the third day ; 
leaves not hurt. 
4. One hundred small trees covered with the Lecanium ; sprayed with 
dilution a, Zamia; scale dead the second day. 
5. Dilution d of b milk sprayed on 20 large trees badly affected 
with Mytilaspis ; 100 gallons used. In a week most of the scales loos- 
ened, and 50 gallons more used cleaned the trees of scales. 
6. Dilution b 1 whale-oil soap ; four large trees required but one appli- 
cation to destroy the scale ; 12 gallons used of dilution. 
7. Dilution b, Zamia, one large tree; one application apparently de- 
stroyed all scale; 1 gallon used. 
8. Five small trees affected with Lecanium needed two applications 
of dilution c, whale-oil soap, to clear the trees. 
9. Four large trees having Lecanium; sprayed with dilution rf, rosin 
soap. Xo effect shown the third day. Applied same dilution. Scales 
loose the second day afterward. 
10. Eight large trees; Lecanium and Mytilaspis; 40 gallons of d, rosin 
soap, in which one pound sulphide of potassium was dissolved. Of this 
one application seemed enough. 
11. A large tree badly infested with Mytilaspis. Three gallons dilu- 
tion a of a milk destroyed the scale at one application. Many leaves 
dropped a few days afterward. 
12. Four small trees alike affected with Lecanium. Two sprayed with 
dilution c, rosin soap; scale loose the third day. Two sprayed with di- 
lution c of b milk. A few scales alive on the third day. 
13. These experiments were repeated with the general formula of one 
pound potassic sulphide to 40 gallons of emulsion, with the apparent 
effect of making a dilution ranking as d as valuable as that of the 
a grade. 
I think it reasonable to infer from these experiments : 
1. The soap solutions are more effective in all grades of dilutions than 
those corresponding of the zamia or milk ; the potash doubtless aiding 
in softeuing the scale. In fact, in many cases, strong solutions of soap 
or potash have been used with good effect upon scale insects. 
2. After a rain, or in the evening, all applications are more effective. 
3. Two or more applications of an emulsion containing 1 or 1.25 per 
cent, kerosene are better than a single one of a 5 per cent, or greater 
percentage, of kerosene, and far less liable to injure the foliage. The 
expense of making and applying the emulsions is often greater than the 
cost of the material used, and this will most likely cause strong solu- 
tions to be in greatest demand. 
