LETTER OF TRANSMITTAL. 
Office of the United States Entomological Commission, 
1700 Thirteenth Street, Northwest, 
Washington, D. C, November 15, 1879. 
Sir : We have the honor herewith to transmit to you the Second Ee- 
port of the United States Entomological Commission on the Eocky 
Mountain Locust, or grasshopper of the West. The report is the result 
of the labors of the Commission during the years J 878 and 1879. In 
transmitting onr First Eeport we endeavored to show that it was prac- 
tically exhaustive of one phase of the inquiry, viz, the subjection and 
destruction of the young or unwinged insects as they hatch out in the 
more fertile portions of the trans-Mississippi country. We at the same 
time laid stress on the fact that it was impossible in so short a time to 
properly study the second phase of the question, one most difficult and 
most important, in our judgment, viz, how to prevent this fertile country 
from being overrun by the disastrous winged swarms from the North- 
west. This fact cannot be better set forth than in the following portions 
of our letter to Dr. Hayden, submitting that report : 
The young insects as they occur in the more fertile States affected can be mastered, 
as the Report will, we hope, abundantly prove. We point out the way, also, which 
we have every reason to believe will prove feasible and practicable, to prevent future 
incursions of the winged swarms. 
While it has been the object of the Commission to cover as much ground as possible, 
so as to make this annual report as full and reliable as the time would permit, there 
y*t remain several important subjects that it has so far been impossible to properly 
and exhaustively study. 
The territory affected is so vast, embracing about 2,000,000 square miles, that much 
of it was imperfectly explored, especially in the Northwest. Mr. Riley had to cut 
short his investigations in British America both for want of time and want of funds. 
For similar reasons, and on account of Indian troubles, Montana, Wyoming, and Dakota 
have been but superficially explored. 
The year 1877 was an abnormal year, i. p., the winged insects had the previous year 
overrun and laid eggs in a large section of country in which the species is not indige- 
nous, and a numerous progeny hatched in such country the past spring. This was 
most fortunate for many reasons, as it enabled the Commission to carefully study the 
insects in this their unnatural condition, and to carry on experiments with a view of 
learning how best to control them. Much of the work of the Commission was with 
these young insects. The losses sustained through the devastations of the pest by a 
young and struggling frontier population, ill able to bear them, were immense, and 
there was so much discouragement that hundreds and thousands of persons were on 
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