248 GEOLOGICAL SURVEY OF THE TEERITORIES, 



Another serious drawback to tlie agriculture of Colorado, as well as 

 other portions of the great trans-Mississippi plains, is the destruction of 

 crops by the migrating grasshoppers. During some years, in difi'erent local- 

 ities, these insects have proved very destructive, sometimes sweeping away 

 in a few days the result of the hard labor of the farmer during an entire 

 season. Yet I find, after a somewhat thorough examination, that in this 

 Territory although occasionally very injurious, yet they are by no means 

 so destructive as has been represented. And, as has been the case this 

 season, the papers of this western country often imprudently spread false 

 alarms. This arises from a neglect to distinguish the larvfe of the migra- 

 tory species from those that are merely local. I am satisfied that there 

 is but one migratory species — the Caloptenus spretws — which appears here 

 in any considerable numbers. The Oedipoda eoraUijes (Hald.) is found 

 at certain points in limited numbers, but I do not think it ever proves 

 destructive east of the mountains. 



I have noticed during our trip the former species at various points as 

 follows : 



On our arrival at St. Joseph, Missouri, June 17, we found them very 

 abundant in the complete state, so much so that the lower i^arts of the 

 walls of the hotel at which we stopped were literally covered black with 

 them, and the hogs, which seemed to have learned the art of catching 

 them, were enjoying a rich feast. I understood they had been moving 

 for something over a week previous to the date of our arrival. 



At Omnha, Nebraska, the 18th of the same month, I saw none of them. 

 It is true I did not go out of the city to examine, yet I think if they had 

 been present in any considerable numbers I should have seen them. 



During our stay at Cheyenne, (from 21st to 28th June) I noticed them 

 in considerable numbers, but in the larva state and scarcely half grown. 



At Box Elder Creek, and Laporte, on the Cache a la Poudre, I saw none, 

 although I made diligent search for them ; but when we arrived at Big 

 Thompson, two days after, (July 3,) I found them quite abundant in the 

 perfect state. From here to Clear Creek, Denver, but few were seen. At 

 the latter place (July 7 toll) I observed them in moderate numbers, just 

 entering the perfect state, butthe local species were rather numerous, both 

 in individuals and species. From here we passed westward into the Mid- 

 dle Park (from July 15 to 27) and all along the moimtain valleys, after enter- 

 ing the first range, and in the park we found them in abundance in the 

 perfect state, often rising, when the wind was prevailing, in large swarms 

 and floating before the wind like huge flakes of snow. I traced them even 

 up into the very midst of the eternal snows, gathering specimens from 

 the cold surface 5 and, strange as it may seem, even above the snow, on 

 the naked summits of the peaks, I saw the larvae of this species hopping 

 about almost as lively as those on the plains. 



After crossing the South Platte, going south, although individuals 

 were occasionally seen, yet at no place during the remainder of the 

 journey were they seen in abundance. 



One conclusion to be drawn from the foregoing facts is that, even 

 within the limits of the eastern portion of the Territory, there are 

 distinct local broods; for while they were abundant and active, in the 

 perfect state, at Big Thompson, July 3, yet, on Clear Creek, about a week 

 later, they were undergoing theii' last moulting, and between these 

 points scarcely any were found. 



Another important conclusion which I think we may draw from 

 these facts is, that the mountain canons and vallej^s are the primary 

 hives from which these vandal hordes issue upon their destructive mis- 

 sion — important because it renders the problem of counteracting them 



