212 INSECTS AFFECTING VEGETATION 



by means of upright stakes and a strip of muslin. In the pan is 

 placed a quantity of kerosene or crude petroleum, or a small amount 

 of water with oil upon the surface and the pan or dozer is then 

 drawn over the field by hand or by means of a couple of horses kept 

 well apart so as to collect the hoppers. If the horses are in front of 

 the middle of the pan, many of the hoppers will jump out at the sides 

 and escape the pan. Every hopper that gets wet with the oil dies. 

 Many will jump into the oil and jump out to die. When they be- 

 come abundant in the pan, they should be thrown out. (Press 

 Bui. 19, Col. Agr. Exp. Sta.) 



Rocky-Mountain Locust. The permanent breeding grounds 

 of this locust extend chiefly along the eastern Rocky-Mountain 

 range, from longitude 102 to 140 west of Greenwich, and from 

 latitude 53 to 40 north, comprising most of the levels below an 

 altitude of 6,000 feet and above 3,000 feet. In many portions of 

 this area they breed every year, and lead an essentially migratory 

 existence. This permanent breeding area gradually shades into a 

 sub-permanent region, in which locusts breed more or less fre- 

 quently, and which is liable to be invaded at any time or rather 

 whenever the insects become very numerous in their true breeding 

 grounds. This region includes a large portion of British America, 

 nearly all of the Dakotas, Western Nebraska, Northwest Kansas and 

 the northern half of Colorado. Although Minnesota may be said 

 to be located in the temporary region, i. e., a region only periodic- 

 ally visited, yet parts of the state are unpleasantly near the bound- 

 ary or danger line, and therefore apt to be overrun by hordes of 

 hungry locusts, and such has been frequently the case, as can be 

 seen in former reports. From 1863 to 1878 there was hardly a 

 year in which locusts did not occur in sufficient numbers to injure 

 the crops somewhere. When not occurring elsewhere they were 

 surely found in the Red River Valley. They did not breed there 

 during all these years, but sufficient new swarms came from the 

 northwest to recruit the invading army and make it formidable. In 

 1877 they destroyed alone in nineteen counties 337,188 acres of 

 wheat. (Bui. 17, Minn. Agr. Exp. Sta.) 



Grasshoppers in Alfalfa Fields. Of all the insect pests which 

 are found in Nevada the grasshoppers are most destructive, for they 

 injure our most important industries, agriculture and stock rais- 

 ing, by invading the alfalfa fields. They usually do the greatest 

 damage to the second crop of alfalfa, for, though they hatch in 

 spring from eggs laid the previous autumn, the young hoppers do 

 very little apparent injury to the first crop. As soon as it is cut, 

 however, they are deprived of their abundant supply of green food. 

 The few leaves remaining are quickly destroyed, and with them 

 every opening bud and newly-formed leaf. The second crop can- 

 not make a start for the new growth is eaten as fast as it appears. 

 The injured fields sometimes look as bare and brown in midsum- 

 mer as they are early in spring. In many cases this means the loss 

 of thousands of dollars worth of hay, 



