June, 1922 bionomics of alphelinus semiflavus 211 



Osburn for suggestions and corrections in manuscript. Many 

 thanks are given to Prof. T. H. Parks for useful suggestions on 

 rearing methods and recording of data; to Dr. C. H. Kennedy 

 for aid in microtechnique and drawing; and to the entire staff 

 of the Department for aid in advice and equipment. 



Among those outside the University to whom the writer is 

 especially grateful, are Dr. L. O. Howard, authority on aphis- 

 feeding Aphelinids, who very generously gave of his valuable 

 advice, and assisted greatly in the confirmation of records and 

 determinations; Mr. A. B. Gahan, of the National Museum, 

 for determining the parasites; Mr. T. L. Guy ton, of the Penn- 

 sylvania Department of Agriculture, for determining the aphids; 

 and Dr. Paul Marchal, director of the Entomological Station, 

 Department of Agriculture, Paris, France, for giving first hand 

 his experience in colonizing Aphelhitis mali How. in France. 



METHODS AND APPARATUS. 



Practically all the data included in this paper are from 

 indoor rearing, either in a greenhouse or room. Most of it was 

 carried on in the greenhouse insectary of the Ohio State Uni- 

 versity, and near a window in room 107 of the Botany and 

 Zoology building. The observations made in Pennsylvania were 

 taken on material grown before an open window in the writer's 

 private room in Oak Lane. That the results thus obtained 

 should vary with outdoor conditions is a fact which must not 

 be overlooked; especially since experience has shown Aphelimis 

 to be quite sensitive to slight temperature changes below a 

 certain point. 



The temperature in the greenhouse insectary varied from 

 50 degrees Fahr. on cold winter days, to 100 degrees on warm, 

 sunny days of early fall and late spring. For the greater portion 

 of the time, it remained between 70 and 80 degrees Fahr. The 

 room in the Botany and Zoology Building stayed very close to 

 70 degrees all the time. No temperature readings w^ere taken 

 for Oak Lane, but here it was very near outdoor temperature 

 during the summer and warm room temperature (70 degrees 

 and above) for the winter. 



Light and humidity were not measured. 



Those cages which gave the most satisfaction in the matters 

 of light, ventilation, security, and accessibility, were the. 



