242 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



damaged beyond doubt, many leaves being brown and heavily infested. 

 The oats were two-leaved and 100 per cent infested. In the wheat 

 fields where we found parasites plentiful in the fall, today we found 

 some half dozen brown parasitized aphids. The individuals parasitized 

 had crawled up to the tip of the topmost leaf of the plant, where they 

 had changed to the brown form. This seems to be a characteristic of 

 the parasitized aphid, and owing to the scarcitj^ of them, it assisted us 

 greatly in finding them. A large number of the living aphids were col- 

 lected from wheat plants, and placed in a breeding cage; no parasites 

 were reared from these, which indicates that the adult parasites had not 

 been active in this field for some time in the past, probably not since 

 last fall. About seven miles south of Hunnewell, Kansas, the fields 

 were heavily infested, and here we found a few more of the parasitized 

 aphids on the top leaves. Again we collected a large number of aphids 

 and put them in breeding cages, from which no parasites were obtained. 



Cooperation with State Officials 



The apparent absence of the parasite from practically all of the fields 

 in southern Kansas in April afforded an excellent opportunity for the 

 study of parasite introduction. Representatives of the Kansas insti- 

 tutions came to Wellington on April 28, for the purpose of investigating 

 the fields and to determine whether the parasites were present, and if 

 they were absent, whether we could find a field to the southward where 

 they were present in sufficient numbers that we could collect large 

 numbers and later introduce them into the fields. Upon the arrival 

 of the officials, we held a conference, wherein we decided that we would 

 go together in the automobile of the department to the various fields 

 in the vicinity of Wellington, and make a close search for the parasite. 



Introduction of Parasites 



On the 30th of April a slight misty rain fell all day. It was very cool 

 and disagreeable, the wind being from the north. This was followed 

 on May 1 by another cool day, with the wind in the northeast, threat- 

 ening rain all day. However, in company with Messrs. Hungerfotd, 

 Wellhouse, and Lawson, of the University of Kansas, T. H. Parks of 

 Manhattan, who replaced McCoUoch, and E. L. Barrett, my associate, 

 we began investigation of the fields in the vicinity of Wellington, for 

 the purpose of determining whether the parasite, Aphidius testaceipes, 

 was present. The oat and wheat fields on this day were generally and 

 evenly infested, no spot more infested than another. Large numbers 

 of the winged forms had flown into the fields and had started small col- 

 onies. Some of the offspring of the winged forms had reached maturity 



