15 
As a result of a continuation of this rotation the pest has been practi- 
cally exterminated, thereby, according to Mr. Fowler’s estimate, saving 
him $10,000 per annum. 
Professor Osborn has shown that grass insects destroy much produce. 
He estimates that the small leaf-hoppers (Jassidw) destroy as much food 
from two acres of pasture as would feed one head of stock. From re- 
cent experiments he has found that it is possible by the use of hopper- 
dozers to reduce the numbers of these insects so materially that, upon 
two plots chosen for their similarity of the conditions of the growth, 
the amount of hay produced upon a plot which was once treated with 
the hopperdozer was 34 per cent greater than upon the corresponding 
untreated plot. 
I have said that the study of economic entomology is many sided and 
requires many workers. It is equally true that all who would keep up 
with the rapid development which is going on all the time must work 
day and night, early andlate. The various habits of so many different 
objects of study, many of them nocturnal, require constant attention. 
In conclusion, I would urge on every one the great importance of keep- 
ing the most careful notes of everything which affects their work, not 
only of what is seen in one’s own investigations, but of whatever is 
found in the literature of the different subjects studied. There is per- 
haps no detail of our work which so well repays the slight extra trouble 
which it involves as making all notes carefully, completely, and neatly, 
and then putting them away systematically, so that they can be found 
when required suddenly on some future occasion. Our “ private notes,” 
as we call them, should, I think, be made with the greatest possible 
care, not only for our own sakes, but to insure that they may be of use 
to others after we are gone. Who has not felt the disappointment on 
looking through the collection of some great worker suddenly called 
away from this life, of finding rare and interesting specimens, without a 
single note of locality, date, or other information, and how compara- 
tively useless such specimens, and even the labor by which they were 
bred or procured, are thus rendered. We all know this, and yet how, 
too often, do we put aside material without labels, thinking that we 
know and shall remember all about them. After many years of much 
wasted labor I have come to the conclusion that a few specimens well 
) preserved, properly mounted, and with full notes, are far more valuable 
than a large number of specimens without these characters. When a 
collector once gets the habit of accumulating a large number of speci- 
‘mens of everything he sees, he very soon gets careless about putting 
them away while they are in good condition, and has not time to make 
the proper notes. 
_ Not only should notes be taken of what we ourselves have seen, but 
much time will be saved if an index book be kent of all literature which 
passes through our hands. Evenin this we must protect our ourselves. 
“The time of an enthusiastic entomologist is necessarily short, and he has 
