Fig. 271. — Caloptenus differentialis. 



ORTHOPTERA. 195 



wet meadows, especially those in which rank weeds occur. The former is confined to 

 the central portion of the United States, while the latter extends throughout the 

 greater part of temperate North 

 America. Caloptenus luridus, which 

 closely resembles the common red- 

 thighed locust, is met with in the 

 Missouri valley, where it is more 

 partial to uplands and more open 

 country than are any of the preced- 

 ing species. Caloptenus cinereus is found throughout the northwestern portion 

 of the United States, where it lives upon several species of Artemisia, or sage 

 brush, the leaves of which it resembles in color. 



No insects have had more said about 

 them, and none have done more mischief in 

 the world than migratory locusts. They 

 are distributed over all parts of the world 

 which possess extended steppes or treeless 

 plains. They flourish on elevated plateaux 

 and in hot and dry atmosphere. They are 



Fjg. 272. — Caloptenus bioittatus. .„ ,. p,,. 



essentially denizens oi the plains, and can- 

 not perpetuate in heavily timbered or in low, humid regions. 



The chief migratory species of the Old World, made famous alike from its terrible 

 destructiveness and its frequent mention in Holy Writ, is the Pachytylus migratorius, 

 which we herewith figure. P. cinerascens is but a variety. While this insect, together 

 with other species, and especially Acridium perigrinum and Caloptenus italicus, have 

 ravaged eastern countries from the earliest historic period, much remained to be 

 learned, up to within a few years, whether as to its habits or as to the best means of 

 controlling it. 



The most injurious species in the United States is Caloptenus spretus, or the 

 Rocky Mountain Locust, alias Western Grasshopper. It has ravaged the country west 

 of the Mississippi, at irregular periods, from the earliest history we have of that country, 

 and it was so very destructive in the northwestern States and Territories from 1873 to 

 1877, that it may truly be said to have been one of the chief causes of the business 

 crisis which characterized that period. So widesjjread and disastrous were the results 

 of its work that Congress provided for a commission to investigate it. As a result of 

 the labors of this commission, the world has a better knowledge of these destructive 

 migratory locusts — their habits, the laws governing their movements, their enemies, 

 and the best way of dealing with them — than it ever before possessed. This infor- 

 mation is embodied in the reports of the United States Entomological Commission, 

 published by the government. 



Caloptenus spretus being thus the best known of our locusts, in all its bearings, we 

 will quote largely from our own writings upon it, because the general facts in refer- 

 ence to it will apply to all migratory locusts, while its development and transforma- 

 tions are typical of those of the whole family. 



" No one who has not witnessed the ravaging power of locusts can fully conceive 

 of or appreciate it. The organization and habit of the typical locust admirably fit it 

 for ravenous work. Muscular, gregarious, with powerful jaws, and ample digestive 

 and reproductive systems ; strong of wing, and assisted in flight by numerous buoyant 



