82 



ELEMENTARY ENTOMOLOGY 



/> 



FIG. 101. Rocky Mountain locust laying eggs 



rt, females ovipositing, with earth cut away to show tip of 



abdomen placing eggs at d, and completed egg mass at c ; 



c, eggs. (After Riley) 



in color, but the hind-wings are black, with a broad yellow edge 



quite conspicuous in flight. Throughout the Mississippi Valley 



the differential locust 

 (Melanoplus diffcr- 

 cntialis) is one of 

 the most destructive 

 forms, being particu- 

 larly injurious after 

 floods, when it multi- 

 plies rapidly on the un- 

 cultivated land which 

 has been flooded. A 

 generation ago (1874 

 -1877), the crops of 

 the western part of 

 the Mississippi Val- 

 ley were utterly de- 

 stroyed for several 



years by the clouds of Rocky Mountain or migratory locusts 



(Melanoplns spretns] which 



swooped down from the 



tablelands of the northwest, 



where they bred and mul- 

 tiplied. Accounts of the 



numbers and voracity of 



these locusts seem almost 



incredible to-day, except to 



those who have seen an 



occasional outbreak in the 



northwest, for with the set- 

 tling and development of 



the western plateau they 



have become less abundant, 



and are now injurious only 



in Minnesota, the Dakotas, 



and Manitoba. In the mid- 



FIG. 102. The Carolina locust {Dissosteira 

 die and Southern States the Carolina], female. (Slightly enlarged) 



large bird grasshopper, or ( After Lugger) 



