IOWA ACADEMY OF SCIENCES. 37 



successful collecting of Mr. E. D. Ball, whose faithful, per- 

 sistent efforts it is a pleasure to acknowledge here. During 

 the summer of 1897 I spent a couple of weeks in the northwest- 

 ern counties, primarily in the investigation of Hessian fly- 

 injuries, but availing myself of such opportunities as pre- 

 sented to collect the Hemiptera, and such collections at Rock 

 Rapids, Little Rock, Storm Lake, Alta, Cherokee and Sioux 

 City, in Iowa, and Sioux Falls, S. D., by myself, and at Little 

 Rock by Mr. Ball, who gave especial attention to the jassidse 

 of the prairie grasses, furnish a basis for the preliminary 

 consideration of the hemipterous fauna of the region. 



It will be noted that nearly all the localities cited belong to 

 the western slope and most of them to the formation peculiar 

 to the Missouri valley. Little Rock is the most distant from 

 the river, but its elevation and the numerous hills and ridges 

 in the vicinity, bearing the sparse vegetation characteristic of 

 the plains farther west, makes it faunally related to the more 

 western localities. The lower levels and river valleys in all 

 these localities present a fauna more like that of the rest of 

 the state, as will be seen by comparison of complete lists, but 

 the portion discussed particularly here is the part that belongs 

 really to the plains region and which is extended into this 

 area because of the conditions prevailing on the more elevated 

 portions. 



Much more attention was given to jassidas than other 

 groups, hence the great preponderance in this family. How- 

 ever, for the region and the vegetation worked, this is a 

 natural preponderence. 



HETEROPTERA. 



Hoiii(f')in(8 biji/fjl.s Uhl., is an abundant species in the region, 

 occuring in rank vegetation of lower levels, and while ranging 

 eastward and in some cases becoming fairly common, it 

 appears to be more particularly typical of the plains. 



Liodenita belfragii Stal., reported in the last proceedings, has 

 not been obtained in Iowa in any other point than Little Rock. 

 Stal. gives its habitat as "America borealis, Illinois.'" 



Peribalus pkeus Dall. Two specimens of this species from 

 Little Rock are the only representatives taken in Iowa. They 

 belong to the boreal fauna, and it is worthy of mention that the 

 only part of Iowa touched by the transition zone, according to 

 Merriam, is the northwestern corner, where these occurred. 



