REMEDIES AM) PREVENTIVES. 109 
each day, the work of control will be facilitated by the fact that most 
of the insects will be on young trees or sli rubbery, winch can be com- 
paratively easily reached. With the larger trees also it 18 true that 
immediately alter emergence the bulk of the Cicadas will be on the 
lower limbs. 
Of the many substances experimented with few proved to be of much 
value, the best results being obtained with 1) Pyrethrum or insect 
powder, using it both in the dry form and as an aqueous solution: 2 
kerosene emulsions: and (3) solutions of various acids. These sub- 
stances either effected the immediate death of the insect, or attained 
this end indirectly by preventing its transformation from the pupal 
to the adult stage; in other words, rendering the last molt impossible. 
Pyrethrum powder is a perfectly satisfactory destroyer of the newly 
tranformed and soft Cicadas, and has considerable efficacy against the 
mature and hardened individuals. The best results are obtained in 
the morning, before the insects have gained full strength to ascend and 
while the plants were still wet with dew. The powder may be puffed on 
the insects while clinging to shrubbery or on the lower branches of the 
larger trees. 
Pyrethrum powder is absolutely worthless against the pupa-, which, 
even when thoroughly coated with it, will often succeed in casting off 
their powdered skins and escape uninjured. The winged insects are, 
however, very sensitive to the powder, and after an application soon 
show signs of uneasiness and in the course of a few hours fall helpless 
to the ground, where, though they may continue to have the power of 
motion for a day or more, a fatal termination is almost sure to follow. 
The pyrethrum and water mixture is prepared by stirring up as much 
of the powder as the water will hold in suspension, or a little milk may 
be added to increase the holding power of the water. The results 
obtained with pyrethrum in water against the transformed insects are 
as satisfactory as with the dry powder, with the additional advantage 
of its being possible to throw the water by force pumps to parts of the 
plant where it would be difficult to place the powder. Against the 
pupa-, the water solution is more effective than the powder, but is less 
so than kerosene emulsion. 
Kerosene emulsion, as an application for destroying the emerged 
pupae and adults, is used in very strong solution, or at a strength 
ranging from one part of the emulsion to one of water up to a dilution 
of the emulsion with eight parts of water. The greater strengths were 
more immediate in their effects, but even with the more diluted washes 
very satisfactory results have been obtained. The emulsion at once 
Stops all molting or transformation. Applied to the partly transformed 
insects, the soft wings harden into shapeless masses, and while occa- 
sional individuals may survive the treatment for two days or more, the 
application is usually fatal in the end. The treated pupa- are unable 
to transform to the adult stage and they eventually die or are devoured 
