201) 



We have, then, as the nearest approximation to the truth at- 

 tainable at the present time: 



Indiana, 66 species, Nebraska, 150 species, 



Illinois, 82 species, Colorado, 133 species. 



The excess in Illinois as compared with Indiana is very 

 largely due to its western sand districts; while the great varie- 

 ty in Nebraska may properly be ascribed to its wide range of 

 soil and climate, from the humid Missouri valley to the arid sand 

 hills of its western part. The suitability of an arid environment 

 for acridiid development is also evident in these figures. A com- 

 parison of the species of the three states first mentioned shows 

 that with the exclusion of the Tettiginre, which cannot be accu- 

 rately compared at present, Nebraska contains nearly all the spe- 

 cies of Indiana and Illinois, and Illinois probably nearly all of 

 those of Indiana. Ten species of Illinois or Indiana do not occur 

 in Nebraska lists. These include two quite rare Illinois species, 

 Mecostethus platypterus and Melanoplus walshi', five northern spe- 

 cies, Trimerotropis maritima, Paroxya scudderi, and P. hoosieri, 

 Melanoplus extremus, and M. islandicus, the last three of which 

 have not yet been taken in Illinois; and three southern species, 

 Trimerotropis saxatilis, Eritettix virgatus, and Melanoplus im- 

 pudicus, the first two not yet taken in Indiana. 



The Acridiidce of Champaign county in the vicinity of the 

 University of Illinois have received a great deal of attention, 

 and 32 species have been taken. This is a typical series of the 

 ordinary prairie and forest, not only of east-central Illinois, 

 but also of Indiana, of western Illinois, and of at least the ad- 

 jacent parts of Missouri and Iowa. These species should cer- 

 tainly be found in the Illinois River valley, as there is no lack 

 of suitable situations for all; they have merely not yet been 

 searched for, except in the sand region. There, 19 of them are 

 known to occur, and the same region, moreover, has 26 species 

 not yet found in Champaign county and not likely to be found 

 there, making an actual total of 45 ( about one half more than in 

 Champaign county), and a probable total for the central lower 

 valley of 58 — nearly twice that of Champaign county. 



