General Considerations. 



231 



seem that the Saskatchawan country must have been more 

 or less depleted by the swarms which overspread the coun- 

 try to the southeast last fall. I am inclined to hope and 

 believe that there will not be another general invasion 

 next autumn, and that the people of Texas, Indian Ter- 

 ritory, Arkansas, Missouri, Kansas, Nebraska, Iowa, 

 Southern Dakota and even Minnesota, may expect 

 immunity for a few years to come, after the hosts which 

 hatched this spring are destroyed, or wing themselves 

 away. There may be partial injury from their progeny in 

 1878, or even 1879, in parts of the country named, espe- 

 cially toward the Northwest, but there will, I think, be no 

 general destruction. 



That in the future the States just enumerated will be 

 again visited from time to time, there can be no manner 

 of doubt, unless the Commission now investigating the 

 subject discover some means of preventing the migrations 

 of the pest from its native breeding-grounds. But the 

 injury will decrease in proportion as the population in- 

 creases — as knowledge and experience with the insect are 

 acquired and retained — and as the Signal Service is able to 

 forewarn the farmer of approaching swarms. It is my 

 earnest hope that this little treatise, which I now close, 

 will, in serving as a record of the past, if in nothing else, 

 prove valuable to the farmers of the West, by helping them 

 to successfully withstand any future visitation of Calopte- 

 nus spretus. 



