[From Report of Iowa of Academy Sciences, Vol. IV. Des Moine?, 1897.] 



CONTRIBUTIONS TO THE HEMIPTEROUS FAUNA 



OP IOWA. 



BY HERBERT OSBORN AND E. D. BALL. 



I. ON THE LIFE-HISTORY OP JASSID^. 

 (With descriptions of new species and a review of the genus Deltccephalus.) 



In various papers published during the past five years the 

 senior author has called attention to the injuries caused in grass 

 lands and pastures by the numerous species of Jassidse, which 

 swarm, often by millions to the acre, upon various species of 

 grasses. 



In these papers it has been shown that the loss, though sel- 

 dom noticed, must be really enormous, and that by the use of the 

 tar pan or "hopper-dozer" the insects may be to a great extent 

 destroyed. Further than this, however, our knowledge has been 

 too meager to furnish a certain basis for remedial measures. 

 It is true studies were made of a few species and ome facts 

 learned as to their life-history which warranted the belief that 

 burnirg, mowing, etc., might be of service, but still so much 

 remained unknown regarding even the most common species, 

 that there seemed a necessity for a more exhaustive study. At 

 the beginning of the present season (1896) a study was planned, 

 the essential features of which were: First, a determination of 

 the life histories of as many as possible of the species known to 

 feed upon grasses. Second, the determination of the range of 



