THOMAS ON ORTHOPTEEA OF DAKOTA AND MONTANA. 49.1 



" their progress was readily traced from the north and west, and their 

 origin was undoubtedly Dakota and l^ebraska, where my friend O. H. 

 St. John observed them in abundance in the hirva state in May. He 

 also noticed them at or near Sioux City, and at other points on the Iowa 

 side of the Missouri Eiver." 



The facts in regard to the direction from which the hordes of 1874 

 came is also corroborative of the opinion advanced. And, finally, a fact 

 which at first appears to stand opposed to this opinion, when carefully 

 considered, really goes to strengthen it, if applicable to the general halt. 

 The evidence in regard to the arrival of the hordes of 1866 in Kansas 

 rather tends to show that they came from the west, and, in some in- 

 tances, from the southwest. As it is shown by equally strong evidence 

 that they did not come from the inhabited portions of Eastern Colorado, 

 they must have come from the intermediate Plains, and if they were from 

 the mountains they must have passed down first, then have changed 

 their course and returned, while another portion passed on to Texas, 

 which is a far more violent presumption than that which I have given, 

 which is, that they were hatched on the Plains as the successors of those 

 Avhich left the northwest in 1864. But where such change of course 

 occurs in the interior of the settled portions, it may be merely a short 

 flight from a neighboring section after their first halt, and argues noth- 

 ing then ; but the evidence in this case appears to apply to their general 

 direction, and not to a merely local movement. 



I have dwelt somewhat at length upon this point, because I have long 

 had doubt in regard to the correctness of the idea that all swarms which 

 invade these border States sweep down from their distant hatching- 

 grounds in a single generation, as if they knew, by a kind of new and 

 recently obtained instinct, rich fields of corn were to be found in Kan- 

 sas, Nebraska, and Minnesota. I had hojied the facts in regard to the 

 recent invasion would settle this question ; but as these have yet to be 

 gathered, except a few which correspond to those of 1867, and agree 

 with the view I have advanced, we must for the present rely on those 

 already known in reference to past incursions. 



It is certainly strange that they should always pass over this belt of 

 two or three hundred miles, on which herds of buffalo have flourished 

 for ages, without making a halt. Where do the numerous hordes go 

 which leave the mountains, but never reach the settlements on the east 

 side? Most undoubtedly, they spend their force upon the Plains; prob- 

 ably finding sufficient nourishment in the grasses of this area, they 

 remain, diminishing year after year in numbers or gradually losing their 

 migratory disposition. 



Let us now consider for a moment the possibility of fighting these 

 hordes from the fields after their arrival, or of destroying them by direct 

 means and mechanical appliances. In the first place, it is impossible 

 to tell just when they are coming and when they will alight, so that 

 even were the national military forces detailed for the purpose in ques- 



