272 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
last two methods arc the only ones which at present we have any faith in 
as capable of sufficiently general application or as resulting in general 
good. The iirst question to consider is whether the insects can be pre- 
vented from migrating from their permanent breeding-grounds, and — 
considering excessive multiplication the immediate cause of migration — 
this virtually means whether they can be prevented from becoming 
excessively multiplied in such breeding-grounds. At first view it would 
seem hopeless to attempt anything of the sort, and a year ago we had 
such a vague and imperfect knowledge of these permanent breeding- 
grounds that any proposition looking to wholesale destruction of the 
insects in them would have appeared Utopian. But we have learned 
enough of the laws governing the movements of the species and of the 
country designated as the Permanent region to give us faith, not only 
in the possibility of thus keeping the species in check east of the Eocky 
Mountains, but in its feasibility. 
" There is a popular notion that this pest breeds in and comes from 
sandy, desert countries. It is a popular error. The insect cannot live 
on sand, nor does it willingly oviposit in a loose, sandy soil. It does 
not thrive on cacti and sage-brush. It flourishes most on land clothed 
with grass, in which, when young, it can huddle and shelter. It can 
multiply prodigiously on those plains only that offer a tolerably rich 
vegetation — not rank and humid, as in much of the prairie of Illinois, 
Missouri, &c, but short and dry — such as is found over much of the 
prairies and plains of the Northwest. Now, the destruction of the eggs, 
which is so practicable and effectual in settled and cultivated sections, 
is out of the question in those vast unsettled prairies ; but the destruc- 
tion of the young locusts is possible. Those immense prairies are not 
only susceptible of easy burning, but it is difficult to prevent the fire 
from sweeping over them. Some system of preventing the extensive 
prairie-fires in autumn that are common in that country, and then sub- 
sequently firing the prairie in the spring, after the bulk of the young 
hatch, and before the new grass gets too rank, would be of untold value 
if it could be adopted. The more we study the question, and the more 
we learn of those breeding-grounds, the more feasible the plan grows 
in our minds. The Dominion Government has, fortunately, a well-or- 
ganized mounted police force, which constantly patrols through the 
very regions where the insects breed north of our line. This force is 
intended to see that the peace is kept, to watch the Indians, to enforce 
the laws, and perform other police duties. It could be utilized, without 
impairing its efficiency as a police force, in the work we have indicated, 
or it might be augmented for that same work. We have conversed with 
the ministers of Agriculture and of the Interior, and with Governor 
ranged with the present Commissioner of Agriculture to have them taken care of at 
the Department grounds before shipping them West. Those that had not died on 
the way arrived in such feeble condition, however, that they soon perished, wirh the 
exception of one which is probably yet living in the neighborhood of Washington 
