June, '21] 



ressler: pyrausta ainsliei 



279 



period lasted from six to ten days. Considerable difficulty was ex- 

 perienced in hatching eggs out in the insectaty at the start due to rap- 

 id changes in temperature and moisture conditions. This was soon 

 remedied, however, and the results obtained in the insectary tallied 

 with the observations in the field. Just before hatching the egg 

 turned a brownish color. 



The larvae of the stimmer generation hatched in the latter part of 

 June and continued through a period until about July tenth. The 

 newly hatched larvae began to feed almost immediately in the mid- 

 rib of the leaf but soon migrated to the stem where they made a cir- 

 cular opening, entering the stem almost invariably just above a node. 



The pupae of this generation were observed about the end of July 

 and the last on August twenty -third. Just before pupating, the lar- 

 vae spun a delicate, white silken curtain across its burrow just in front 

 and back of itself, forming a cell. The pupal stage extended over a 

 period of from nine to fourteen days., the average length being twelve 

 days. The first moths emerged August tenth and were observed in 

 flight until September fourth. These moths began to deposit eggs 





5: 



Pig. 6 Diagram of Life History of P. ainsliei Showing also Average Temperature aad Aver- 

 age Humidity for the Season of 1920 at Ames, Iowa. 



