23 
the name of the crop from the indexes of books in the 
library of this College. 
The great mistake is taking the subject by the wrong 
end; starting by trying to name the insects we meet 
with instead of being content at first to work back to 
their name from observations of their habits and method 
of injury to the crops. We cannot name insects generally 
(that is, the isolated specimens we chance to meet with) 
with certainty. If we consider that in the collection of 
the great British entomologist, J. Francis Stephens, he 
possessed more than three thousand species of British 
Beetles, more than two thousand Two-winged Flies, and 
nearly that number of species of Moths and Butterflies, 
and other orders in corresponding proportions, we shall 
see that it is a perfect impossibility for any one who 
is not able to devote his whole time to the subject to 
have a special knowledge of more than a small part of 
the orders. But the life-histories of about one hundred 
insects we can easily manage, and the importance of the 
subject will well rejoay the labour of what is rather 
putting in form knowledge already possessed than a new 
study. The subject is one of great importance,—a yearly 
drain on our individual and national resources ; and you, 
gentlemen, who go from this College to lay the foundation 
of thoroughly working principles of agriculture in this 
country and our colonies, are those who best can aid us 
in the future. 
rEINTED BY WEST, NEWMAN AND CO., 54, HATTON GAEDEN, LONDON, E.C. 
