GEOLOGICAL SURVEY OF THE TERRITORIES. 283 



have visited portions of the Territory each year since, hut generally confined to partic- 

 ular localities or narrow belts. 



The swarms that invaded Kansas and portions of Western Iowa in 1867 were traced 

 from their hatching grounds in Western Dakota and Montana, along the east flank 

 of the Rocky Mountains, and in the valleys and plains of the Black Hills, and between 

 "them and the main Rocky Mountain range. 



The Hateful Grasshopper reaches perfection only in a hot dry atmosphere. The great- 

 er the heat of air and earth, the brighter the sun, the dryer everything, the more it 

 flourishes. The egg will hatch at a low temperature ; cold will probably not destroy 

 it ; individual insects will endure a wonderful degree of cold, some living through the 

 entire winter here ; but under such circumstances I do not believe that the young will 

 become a perfect insect, capable of perpetuating its species. Heavy dews, frequent 

 showers with prevailing cloudy weather and humid atmosphere are very unfavorable 

 to their growth. Hence I argue that there is no danger of their ever becoming a gen- 

 eral or permanent scourge in the United States. The exceptional seasons, like that of 

 1807, when the season has favored their early development, and prevailing westerly 

 winds carry them steadily and rapidly on their journey, they may invade some of the 

 States of the Mississippi Valley. Their eggs deposited there may even hatch, but I think 

 the product will be a feeble and comparatively harmless generation, from which none 

 will follow. 



In 1852 I first observed the insect in question in the vally of the south fork of the 

 Columbia River, not far from Fort Hall. A swarm lasting two or three days passed 

 over from about W. S. W., moving with the wind, at times darkening the sun, cover- 

 ing horses, cattle, and wagons, against which they were driven. The Digger and 

 Snake Indians were gathering them for food. In 1865, when they hatched here, upon 

 attaining about half their full size, they were attacked by a fly, which, stinging them 

 in the back between the root of the wings, deposited one or more eggs, which produced 

 a large white maggot. The worm subsisted upon the grasshopper, finally causing its 

 death, when it cut its way out and entered the earth. In this way probably half were 

 destroyed, often covering the ground and filling the furrows in plowed fields with their 

 carcases. The remainder took to flight, moving southeast, when their wings were 

 sufficiently developed, and we lost trace of them on the great Plains. In the same 

 year, about the last of Angust, I was in the valley of South Boulder Creek, close up to 

 the Snowy Range, and found the young grasshoppers very numerous, varying in size 

 from those just hatched to one-third grown. I know that winter caught and killed 

 them before they were able to fly out of the valley, or old enough to produce eggs. 



In 1867 1 observedthe same thing in the valleys west of the Snowy Range. Late in that 

 year the Middle Park was also invaded by full-grown grasshoppers that came from the 

 northwest. They deposited eggs in favorable ground. In 1868 those eggs began hatching 

 in the lowest and warmest portions of the Park in June, increasing in July, and con- 

 tinuing through August and into September in the higher portions of the Park, up to- 

 ward its rim, where snow and frost continue later in the spring and summer. The first 

 hatched moved from their native place up the Park eastward, but never got out of it. 

 The later broods never left their hatching ground. All were destroyed by the fall 

 snows. From the middle to the 25th of August, 1868, I was upon and near the Snowy 

 Range east of Middle Park, and on Long's Peak. There was a large, daily flight of full- 

 grown grasshoppers, from about W. N. W., reaching, apparently, to the' highest limit 

 of vision when on the highest peaks. Daily showers prevailed of rain, snow and hail, 

 usually from 12 m. to 3 p.m., and most of the flying insects were beaten down by them, 

 when they became so chilled and benumbed that they never rose again. The snow- 

 fields in many places were literally covered with the dead and dying. Bears were very 

 plentiful feeding and fattening upon them. Hundreds, yes, thousands of bushels might 

 have been shoveled up from the hard snow. 



I know that they did not come from the adjacent Middle Park, because those bred 

 there had not then attained their full growth, and never did, as before stated. The 

 migrating swarms, therefore, must have come from beyond — from the Creeu River basin ; 

 or, as I think, from the wide, hot, dry plains of Utah. 



These notes by Mr. Byers contain so many important facts in respect 

 to the history of this species, that I have thought it best to make very 

 full quotations from them, that they may be on record for future exam- 

 ination. During the expedition of the present year, while traveling up 

 the North Platte, between Fort Fetterman and Eed Buttes, (August 

 20-23), we observed vast nnmbers of this species. They were not on 

 the wing, having to all appearance ended their flight, and were now 

 pairing, doubtless intending to deposit their eggs there. Fremont en- 

 countered a similar swarm in passing over this part of the North 

 Platte Valley. He remarks, " This insect has been so numerous since 



