61 



the region embraced in these studies, is greatly improving. Practi- 

 cally everywhere these insects are rapidly decreasing and getting 

 down to their normal numbers or even below the normal. Of course, 

 the causes for this decrease are various, being somewhat different in 

 each locality affected. These causes were given and discussed to some 

 extent in my report at the close of the season's work during the 

 summer of 1901." 



August 2, 1904, the writer left Lincoln for the j^urpose of visiting 

 southwestern Nebraska and eastern Colorado, taking a daylight train. 

 A careful outlook was kept from the car windows for signs of locust 

 injuries or the presence of these insects in more than ordinary num- 

 bers. Not until after leaving Oxford, however, Avere such indications 

 observed. But from a few miles w^est of that place all the way to 

 McCook it was clearly indicated, both by the presence of the insects 

 on weeds along the right of way and by more or less damage to the 

 outer rows of corn growing near alfalfa and small grain, as well as 

 by deserted and weedy fields. Each of these conditions was occa- 

 sionally quite apparent, even from the moving train, and increased 

 westward. The species of locusts most concerned in these ravages 

 were tw^o: Melanoplus diff erentialis Thos. and M. hivittatus Say. 

 These two forms habitually frequent low ground and other areas 

 overgrown with rank vegetation. 



The morning of August 3 was spent in the vicinity of McCook. 

 Here it was found that several additional species of locusts, like M. 

 femur-Tuhrum DeG. and M, atlanis Riley, were quite numerous, both 

 in alfalfa fields and on the prairies. The deserted fields wdiich had 

 grown up to rank weeds were the homes of still other species, of which 

 /Eolopliis regalis Scudder and Melanoplus laMnus Scudder were the 

 chief forms. These latter were quite partial to Russian thistle and 

 lambs-quarters as food plants. Hesperotettix speciosus Scudder, 

 which is a feeder on Helianthus, was very common, while several of 

 the grass-infesting species were present in numbers above the normal 

 as observed during ordinary years. These latter, however, were con- 

 centrated at places where the grasses still showed green, and possibly, 

 on account of this bunching, their abnormal abundance may have been 

 only seeming. It might be well to state that this particular region 

 was suffering greatly from drought, a fact which undoubtedly had 

 much to do in causing the more than ordinary locust injury. 



Leaving McCook, the writer had an opportunity of seeing the con- 

 ditions along the Republican Valley almost to the southwestern 

 corner of the State. Just beyond the junction of the Frenchman 

 and the Republican rivers it was noted that the drought conditions 

 were less severe, and vegetation improved as we progressed west- 



o See Bui. 38, n. s., Divison of Entomology, U. S. Dept. Agr., pp. 39-49, 1904. 



