In the case of _Icerya purchasi_ the possibilities
of success in checking it by its natural enemies hung at one time upon
a question of specific difference between it and the _Icerya sacchari_
of Signoret--a question of minute structure which the descriptions
left unsettled and which could only be settled by the most careful
structural study and the comparison of the types, involving a trip to
Europe.

CONCLUSION.

I have thus touched, gentlemen, upon a few of the many subjects that
crowd upon the mind for consideration on an occasion like this--a few
gleanings from a field which is passing rich in promise and
possibility. It is a field that some of us have cultivated for many
years and yet have only scratched the surface, and if I have ventured
to suggest or admonish, it is with the feeling that my own labors in
this field are ere long about to end and that I may not have another
occasion.

At no time in the history of the world has there, I trow, been
gathered together such a body of devoted and capable workers in
applied entomology. It marks an era in our calling and, looking back
at the progress of the past fifteen years, we may well ponder the
possibilities of the next fifteen. They will be fruitful of grand
results in proportion as we persistently and combinedly pursue the yet
unsolved problems and are not tempted to the immediate presentation of
separate facts, which are so innumerable and so easily observed that
their very wealth becomes an element of weakness. Epoch-making
discoveries result only from this power of following up unswervingly
any given problem, or any fixed ideal. The kerosene emulsion, the
Cyclone nozzle, the history of _Phylloxera vastatrix_, of _Phorodon
humuli_, of _Vedalia cardinalis_, are illustrations in point, and
while we may not expect frequent results as striking or of as wide
application as these, there is no end of important problems yet to be
solved and from the solution of which we may look for similar
beneficial results. Applied entomology is often considered a sordid
pursuit, but it only becomes so when the object is sordid. When
pursued with unselfish enthusiasm born of the love of investigation
and the delight in benefiting our fellow men, it is inspiring, and
there are few pursuits more deservedly so, considering the vast losses
to our farmers from insect injury and the pressing need that the
distressed husbandman has for every aid that can be given him. Our
work is ele