178 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
was applied freely, the upper surface of the leaves so far as they were not protected 
by others above them being pretty thoroughly wetted. Results far from being sat- 
isfactory. A large number of worms were affected and killed, but a far greater 
proportion did not come in contact with thefluid, and were consequently not affected. 
Experiment 2. — The liquid was again applied by means of the fountain pump, but 
from one side. In this case the jets strike the leaves and branches with considerable 
force, and the liquid is consequently much more scattered than in the application 
from above. The result was that by far the largest portion of the worms were affected 
and killed, but there remained enough on the plants to do serious injury. 
Experiment 3. — The liquid applied as in the foregoing experiment, but from the two 
opposite sides. Two corners of the field were treated in this way. Result : The plants 
were effectually freed from the worms, and only a very few full-grown ones were 
found about twelve hours afterwards. I must state, however, that the amount of 
liquid used in this mixture was very large, estimated at the rate of not less than 80 
gallons per acre. 
Experiment 4. — The liquid applied by means of the parlor atomizer. This could nat- 
urally be carried on only on a very small scale, but was often repeated. The result 
1 can draw from this experiment is that the very fine, mist-like spray of the atomizer 
is most effective, and even more so than a coarse and copious spray. 
One pound of Pyrethruin, if used at the rate mentioned in these ex- 
periments, viz., 200 grains of the powder to 2 gallons of water, could 
thus be diluted with 75 gallons of water, which would be sufficient for 
2 J acres of cotton, calculating 30 gallons per acre. The cost of this ap- 
plication (not counting in labor and machinery), consists only in that of 
the powder, and putting this down at 75 cents per pound, we arrive at 
the amount of 30 cents per acre of cotton. It must further be considered 
that 30 gallons of liquid per acre, applied with the improved atomizers, 
is a liberal allowance, and that, therefore, the cost of the application 
can in all probability still be lowered considerably without loss in 
efficacy. At any rate, this method of applying Pyre thrum is by far 
cheaper and simpler than any other at present known to us. It is of 
course not free from the principal drawback of Pyre thrum as an insec- 
ticide, and a repeated application is necessary to protect the cotton 
from one generation of worms. But even this double application is 
cheaper than the dry Paris-green remedy, as carried on by the sifting 
method. 
5. The tea or decoction of Pyrethrum. — Professor Hilgard, 
who first called our attention to this method of using Pyrethrum, ex- 
presses himself most favorably as to the results of this experiment. 
He says : 
I think, from my experiments, that the tea or infusion prepared from the flowers 
(which need not be ground up for the purpose) is the most convenient and efficacious 
form of using this insecticide in the open air; provided that it is used at times when 
the water will not evaporate too rapidly, and that it is applied, not by pouring over in a 
stream, or even in drops, but in the form of a spray from a syringe with^ne holes in its 
rose. In this case the fluid will reach the insect despite of its water-shedding sur- 
faces, hairs, &c , and stay long enough to kill. Thus applied, I have found it to be 
efficient even against the armored scale-bug of the orange and lemon, which falls off 
in the course of two or three days after the application, while the young brood is 
almost instantly destroyed. As the flower tea, unlike whale soap and other washes, 
leaves the leaves perfectly clean and does not injure even the most tender growth, it 
