58 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



our old seeding dates, but felt more sure of them after having the data 

 from Bryan and Sandusky. We found that for the successful manage- 

 ment of an emergence station the entire time of one entomologist is 

 required. 



We had meetings at both Bryan and Sandusky of farmers and county 

 agricultural agents, and after showing them our equipment and the 

 results, agreed with them on seeding dates. While the migration wire 

 and the egg counts seemed to give the truest record regarding the 

 activity of the brood, the concentration cage was the best asset from a 

 psychological standpoint to gain the attention and support of the 

 county agents and farmers. When they could see a swarm of flies 

 w^hich had emerged within the preceding 24 hours in the glass globe, 

 and found this record supported by egg counts and the catch of the 

 migration \Aire, they were readily convinced that wheat exposed to attack 

 would certainly suffer. The other types of cage gave valuable informa- 

 tion regarding density of emergence and furnished a check on the con- 

 centration cage, the migration trap and egg-laying records. From them 

 we knew that emergence in the concentration cage was nearly normal, 

 not lagging more than a day or two behind that in the cages with field 

 conditions. 



After the experience in Miami County in 1915 and this season's 

 experience, we feel confident that if, in years of Hessian fiy abundance, 

 a half dozen competent entomologist are stationed at six fly-emergence 

 stations in selected localities over our state, we can determine from their 

 observations favorable seeding dates for different sections with about as 

 much certainty and precision as the United States Weather Bureau 

 can predict the weather. While some of the records may prove indeci- 

 sive, others are likely to give a clear record, assisting greatly in determin- 

 ing the trustworthiness of the seeding dates usually followed. We 

 concede that the date, thus found, may be a few days later than the best 

 date for maximum yield, but this latter can hardly be established for 

 years with heavy infestation, and we, therefore, favor finding the safest 

 date it is possible to discover. 



Result of Late Sow^ing Campaign of 1920 



The daily emergence and egg-laying records were wired or mailed to 

 the county agents in the counties it was desired to guide, and it was 

 found necessary to delay seeding several days longer than the dates 

 at first selected to sow by some of these count\' farm bureaus. On 

 September 25th, the emergence and egg-laying had subsided greatly 

 at Bryan, and two days later at Sandusky. Analyses made of "flax- 

 seeds" in the old stubble showed that most of the flies had emerged. 



