846 ZOOLOGY INSECTS. 



this being 1 a different species from a specimen obtained in California, I am 

 now able to set all doubts at rest, and state positively that the two are quite 

 different and distinct species. 



The collections of 1873 and 1874, as will be seen, contain a number 

 of new and interesting species, especially of Caloptcm and CEdipodce, but 

 it is somewhat singular that so few specimens of Caloptenus spretus, the 

 destructive grasshopper of Utah and the West, are found in them. This 

 certainly indicates that the line of your survey was along the southwestern 

 border of its district. In fact, the collection of 1871 did not contain a single 

 specimen, which was somewhat surprising to me, as I am aware from personal 

 knowledge that its migrations extend along the line of the Central Pacific 

 Railroad some distance west of Salt Lake. 



The absence from the earlier collections of GEdipoda atrox, Scudd., 

 which corresponds exactly with the fact presented by my own collections 

 from Salt Lake north to Montana, is somewhat puzzling when connected 

 with the additional fact that specimens of this species have been found on 

 the; mountains about Yellowstone Lake, and also on the mountains in Cen- 

 tral Colorado. This species is found in abundance in California, where it is 

 not only destructive, but to a certain extent migratory. It is therefore quite 

 strange that it should be absent from the intermontanc plains and valleys of 

 Utah, Idaho, and Nevada, and yet be found in the higher mountain regions 

 of Colorado and Wyoming. The same thing also appears to be true in 

 regard to some other Californian forms, which reappear in the mountains of 

 Colorado. 



Your collection also corresponds in another somewhat singular respect 

 with the collection I made in 1871 in Northern Utah and Southeastern 

 Idaho. While the Rocky Mountain range appears to form a boundary to the 

 range of the species of Locustidce, on the other hand, the distribution of the 

 Acridities appears to be but little affected by it ; for example, Stcnobothnis 

 coloradus, which I supposed was confined to the eastern slope and eastern 

 plains, I find in this collection. (Edipoda ncglccta, which, although a west- 

 ern species, is found as far east as Illinois, is contained in your collection, as 

 is also (E. rhictii, which rc;ichcs eastward to the Mississippi River. 



Pedioscertetes m'radriMx, which is very closely allied to A<rohpliitita 



