110 THE PERIODICAL CICADA. 
by their natural enemies. The death of the mature and hardened 
insect is caused by closing its breathing pores with the oily mixture, 
and in the case of the partly expanded or soft, immature individuals 
by the caustic effect it has on the forming wings and soft body. 
The experiments with acids demonstrated also that exuviation may 
be prevented by spraying the newly emerged pupa with a 2 per cent 
solution of carbolic acid or a 15 per cent solution of acetic acid. 
In view, however, of the difficulty of controlling this insect on a 
large scale after it has once emerged, it is well to adopt any precaution- 
ary measures that may tend to lessen or distribute the injury. The 
advent of all the large and well-recorded broods is commonly heralded 
in advance in the local papers by State entomologists or other persons 
who take interest in such recurrences. Forewarned in this way, much 
injury and loss may be avoided by neglecting all pruning operations 
during the winter and spring prior to the expected appearance of the 
Cicada, in order to offer a larger twig growth and distribute by this 
means the damage over a greater surface. Another precaution, when 
a cicada year is expected, is to defer the planting of orchards, espe- 
cially in the vicinity of old orchards or forest land, until the danger is 
past. The same advice applies to budding or grafting operations in 
the fall and and spring prior to the Cicada's appearance. Much disap- 
pointment arising from injury to orchards or valuable nursery stock 
may thus be avoided. Vigorous young trees will, it is true, often 
recover in three or four years from the effects of a loss of or injury to 
a considerable percentage of their branches, but it is difficult to over- 
come the unsymmetrical appearance which will commonly result from 
the indiscriminate pruning caused by the work of this insect, and the 
gnarled and scarified branches will long bear testimony to the industry 
of the female insect. 
Much of the injury occasioned by the cutting of the twigs by the 
female Cicada in depositing her eggs can be remedied by subsequent 
proper treatment of the wounded plant. In the case of old trees, the 
main object to be secured is the rapid healing of the wounds and the 
prevention of their being used as points of secondary attack by other 
insects. The worst injured limbs in such trees should be cut out, so 
that all the vigor of the plant may be directed to the remaining wood. 
Any treatment also, as of thorough cultivation or the use of fertilizers, 
which will give the plant a more vigorous growth, will hasten the heal- 
ing process. With young trees the worst affected branches should be 
removed, and the less injured ones protected from other insects while 
they are healing by coating the wounded parts with grafting wax or a 
moderately hard soap. These protective coverings should be renewed 
at least once a year, preferably in the spring, until the wounds are 
entirely healed over. In the case of a badly injured tree that has been 
recently budded or grafted, it may be well to cut it back nearly to the 
bud or graft, so that an entirely new top may be made, 
