49 



Smithsonian report of 1858, we find that these insects were very- 

 destructive to the grass of the plains that year, from the Upper Mis- 

 souri to Fort Kearney, and migrating. There may be no connection 

 between the two, but subsequently, in 1871 or 1872, swarms appear to 

 have passed up from Dakota to Manitoba, indicating a disposition in 

 this northern section to move northeast. In 1864 we hear again of 

 invasions of Manitoba and Minnesota, and this year the great hatch- 

 ing ground appears to have been the Upper Missouri and Yellow- 

 stone region. But the great mass this season appears to have spread 

 southeast, and east upon the plains, sending a strong wing down the 

 mountain flank to Colorado, and another detachment into Minnesota, 

 but not reaching the settlements of Nebraska and Kansas. 



In 1866 we find them spreading over Nebraska and Kansas, and 

 even reaching Missouri and Texas, an invasion which has almost 

 universally been attributed to a direct importation from Colorado. 

 Is this opinion correct? Was it not in fact a continuation of that of 

 1864, and if so thus showing that these invading hosts have interme- 

 diate stopping grounds on the great plains as did the advancing 

 hordes of Asiatic locusts in Europe, and probably beyond the Bos- 

 phorus ? In the first place there is no sufficient proof of any such 

 swarms leaving Colorado in 1866, but, on the contrary, the most com- 

 petent authority in the Territory, Colonel Byers, asserts the opposite 

 in his letter to me which is published in the report of Haydeirs Geo- 

 logical survey for 1870. In the second place, as it appears that the 

 great hive of 1864, from which the swarms issued, was Eastern Mon- 

 tana, Western Dakota and Northeast Wyoming, it is scarcely proba- 

 ble that it would send forth but two lines, one toward Minnesota and 

 the other toward Colorado, and these at right angle to each other, 

 while the usual direction of the air currents, by which they are car- 

 ried, is along the diagonal. Again, the advanced guard of those 

 which reached Colorado, and which doubtless came from the nearest 

 hatching ground, after stopping here a short time, passed off southeast 

 in the direction of the Arkansas river. We hear nothing further of 

 them in 1865 ; but as the remaining portion of the horde of 1864 

 stopped in Colorado it is not probable these proceeded very far, but 

 deposited their eggs in Southeast Colorado. JThe brood of 1865 may 

 have advanced but a short step farther, and then in 1866 those which 

 entered Texas were the first of the advancing column, for it was not 

 until 1867 that the storm fell in its full force upon the interior of the 

 State, and that not until late in the season — October and November. 



Advancing north Ave find a corresponding state of affairs. Those 

 which hatched in Colorado in 1S65 left there in June and passed out 

 upon the plains. By turning to the monthly agricultural report of 

 1868 we find it stated that they were in Arkansas, (Montgomery 

 County), in 1867. If we suppose those from the section further north 

 moved in a southeast direction they would probabl}'- have reached the 

 regions of the Black Hills of Dakota, and it is from this region it is 

 supposed by some those that visited Iowa in 1867 came. The time of 

 arrival in Kansas and Nebraska would show a similar rate of progress 

 to the lines already traced, and on this point we have some very strong 

 corroborating testimony. 

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