THOMAS ON ORTHOPTERA OF DAKOTA AND MONTANA. 485 



19. CeutlioijMlus ? 



Specimen too much iujurecl to determine the species ; probably C. 

 divergens Scuclder, which, so far as preserved, it strongly resembles. 



20. Udeopsylla rohusta Scudd. 



This species, though never found in considerable numbers in any place, 

 is nevertheless found over a great part of the West. 1 recently observed 

 it at Bloomington, 111., while attending a teachers' natural history insti- 

 tute held at that place, which shows it is found east of the Mississippi 



21 and 22. Anahrus purpurascens Uhl. 



I may add also A. coloradus Thos., which, though not found in the 

 collections, I received from Manitoba from another source. 



23. Phaneroptera curvicauda Serv. 



As the specimen is alcoholic, and much smaller than usual, I have 

 placed it in this genus with some doubt. 



24. Orchelimum ? 



25. Gryllus ahhreviatus Serv. 



There are several specimens in the collection, some in the pupa state, 

 and some apparently in the perfect state ; but they are much smaller 

 than the usual size of this exceedingly variable species. They may 

 possibly belong to Scudder's G. niger. 



NOTE 0:S CALOPTENUS SPEETUS. 



The great locust invasion of 1874, and the resulting broods of 1875, 

 have called renewed attention to this species, and have brought it more 

 prominently before the world than it has ever been heretofore. They 

 have raised several important questions, both economic and scientific, 

 some of which may ultimately be distinctly and satisfactorily answered, 

 while others will perhaps always remain matters of conjecture only. 

 Among the economic or practical are the following: — Are there any 

 means of preventing their migrations'? and, if so, what are they, and are 

 they practicable? What means have the agriculturists of defending 

 themselves against their attacks? As relating to both the scientific 

 and economic are the following: — Were there such eruptions into the 

 same regions before the entry of civilized man? Are their incursions 

 growing more and more frequent, and are their limits being extended 

 farther and farther eastward? If the facts require this last question to 

 be answered in the affirmative, then how is it to be accounted fori Is 

 there any danger of their becoming permanent residents of the Missis- 

 sippi Valley ? Is it at all likely that they will ever penetrate to the 

 States east of the Mississippi? Is C. spretiis a distinct species, or are 



