22 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
only does it prevent the number destroyed from migrating, but for eacfi 
one killed, so to speak, an entire family brood of the next or migrat- 
ing generation is destroyed. In other words, the destruction of thou- 
sands there would be as effectual as destroying millions of the migrating 
swarms. The means of destroying the young, as before stated, can be 
made more effectual in the sections where irrigation is carried on than 
where it is not. 
As shown in our first report the destruction of the young locusts 
bred in the temporary region from the invading hordes not only gives 
immediate relief but also tends to postpone future invasions by so less- 
ening the numbers in the returning swarms that a longer time is re- 
quired for development. With an agricultural population in the area 
designated the work of destruction would then be carried on at each 
end of their migratory route. 
Here we may also remark that the present idea of making that sec- 
tion of our country peculiarly pastoral area, while doubtless profita- 
ble to the present and for two or three generations to come, will in the 
end entail hardships upon those to follow. It can no longer be doubted 
that while the destruction of forests was the chief agency, yet the pas- 
toral habit of the people of Western Asia and other Oriental countries,, 
once so fertile but now barren, was one important factor in producing 
the present dry and barren condition of those countries, ifo country in 
the interior of a continent, unless supplied with numerous lakes or nu- 
merous and permanent rivers, can remain permanently fertile and pro- 
ductive if given up largely to pasturage of sheep, goats, and cattle 
without cultivation. The rapid destruction of the mountain forests, and 
pasturing their slopes and bordering plains, will most certainly have a 
tendency to render that portion of our country more dry and barren. 
Unless, therefore, our government adopts some policy by which an 
agricultural population can be thrown into that area the day will most 
assuredly come when it will be as barren and desolate as the plains of 
Arabia. The development of the locusts is but an incident of the 
change from a former condition of abundant moisture to the present dry 
one. But this branch of the subject we propose to omit at present. 
It will be seen, therefore, by the foregoing that we think it is possible 
to modify to a very large extent the operations of the locusts so far as 
these relate to the area along the east tiank of the mountains ; and that 
the general government may, without any very great expense, very 
greatly assist in the work. 
It is proper to state here, before leaving this part of our subject, that 
we have not suggested the building of a railroad along the belt desig- 
nated without some knowledge of the difficulties in the way of such a 
scheme. Instead of following the valley of some stream it would have 
to cross alternately narrow valleys and broad elevated plateaus its en- 
tire length, but the difficulty in this respect would be no greater, and 
perhaps not as great, as that experienced in running the Northern Pa- 
