Home, and Range East of Mountains. 



59 



the time and direction from which they came. These attacks are 

 all represented as coming from the west, north or northwest, and 

 reached the Red River Settlement in the last week of July, 1818, 

 the Upper Mississippi about the same time in 1856, the western line 

 of the State in the former half of July, 1864, and on July 15th, 

 1874. In the last three cases the invasions did not reach their 

 farthest limit until a considerable portion of the crops had been 

 harvested. 



If Mr. Scudder means that the hordes that in August 

 and September occasionally overrun the whole territory 

 which I have indicated as outside the insect's natural 

 habitat, originate within or upon the borders of that terri- 

 tory — the country south of the 44th parallel and east of 

 the 100th meridian — then the facts are entirely against his 

 supposition. The late swarms of 1874 and 1876, are known 

 to have traveled from five hundred to six hundred miles 

 after having reached the more thickly settled country. 

 Late appearance and late egg-laying imply late hatching, 

 which, in the main, must needs have taken place in north- 

 erly or sub-alpine regions. The invasion of the northern 

 regions of Minnesota, Dakota, Montana and Manitoba, 

 from the still farther northwest, also makes it clear that 

 the insects come from beyond. The theory of short 

 flights and development, in the immediate vicinity of the 

 country devastated, will not answer for the late disastrous 

 and general irruptions like those of 1866, 1874 and 1876 ; 

 and in discussing this question the difference between 

 these irruptions and the earlier, more frequent and less 

 disastrous ones, should always be borne in mind. 



The species, as defined in this work, and as it swoops 

 down from the mountain region, does not, as some claim, 

 occur every year in Missouri, Texas, Kansas, or any of the 

 country to which I have indicated it is not indigenous. 

 It occurs there only as the dwindling progeny of the 

 swarms from the west or northwest, and never becomes 

 acclimated. I have traveled through Iowa, and from 



