47 



Fort Laramie to the Arkansas river; in Laramie Plains and around 

 Fort Bridger ; from Utah lake, in Utah, to Fort Hall in Snake river 

 valley, Idaho; in Northwestern Dakotah, near the Red River of the 

 North, and on both sides of the range in Montana along the valleys 

 of Deer Lodge river, and the branches of the Upper Missouri. I also 

 obtained satisfactory proof of the same thing occurring in British 

 America, north of Dakota, in Middle Park, Colorado, and in the re- 

 gions west of that point ; in Wind river valley in Wyoming, in 

 Central Montana along the Yellowstone, and in the Green River, 

 country west of South Pass. These facts, which are but a small por- 

 tion of what might now be gathered, will give some idea of the work 

 necessary to be done, if we undertake to exterminate these insects by 

 destroying their nests in their native haunts. 



I will present some facts in regard to their migrations in and 

 from the mountains and northern regions which will assist the reader 

 in forming a more correct idea of their habits and the extent of their 

 operations; and here, be it remembered, that I confine myself to the 

 single species Caloptenus spretus. I have traced a swarm from the area 

 west of South Pass to their stopping place and hatching ground north 

 of Fort Fetterman, from Northwestern Dakota nearly to Lake Winni- 

 peg, and have ascertained that some swarms have even extended their 

 migrations, from supposed southwest point as far as the north side of 

 this lake. It is also known that in one instance, at least, those which 

 left Colorado moved in the direction of Texas ; those visiting Salt 

 Lake Valley have repeatedly come from the northeast, sometimes, 

 doubtless, from Cache and Bear River valleys, and at others from the 

 Snake river region while thosje hatched in the Salt Lake regions 

 moved south, in some instances returning with the change of wind. 

 In 1864 those hatched east of the mountains in Northern Wyoming 

 and along the YeMowstone in Montana, swept down the east flank of 

 the range upon the fields of Colorado, while a part moved east to 

 Manitoba and Minnesota. In 1867 a swarm from the west side of the 

 range poured into Middle Park and there deposited their eggs, but 

 those hatched from these failed to scale their rocky bounds; yet while 

 these were vainly striving to leave their mountain prison, another 

 horde from the barren regions beyond sweeping above them over the 

 snowy crest, poured down upon the valleys east, and in another in- 

 stance a swarm was seen passing for two days over Fort Hall from the 

 southwest. On the other hand we find them extending their flight 

 far into Texas in destructive hordes, yet New Mexico and Arizona 

 appear to be comparatively free from them, at least the very exten- 

 sive collections made by Lieutenant Wheeler's expeditions in these 

 territories during the last four years, which have been submitted to 

 me, contain but very few specimens of the C. spretus, and during my 

 visit to New Mexico in 1869 I found scarcely any specimens south of 

 Raton Mountains, although comparatively abundant in Colorado and 

 even in San Luis Valley- I am therefore inclined to doubt the cor- 

 rectness of the statement made in reference to the grasshoppers in 

 these territories in 1855, if intended to apply to this species. 



These facts if added to the experience of the last three years in Kan- 

 sas, Nebraska, Dakota, Minnesota and Manitoba, will suffice to show 

 not only how extensive the range is, but also how varied their flight, 

 and that there are no particular spots which can be said to form their 



