April, '17] KELLY: GREEN-BUG OUTBREAK 243 



and had begun to reproduce. "We carefully looked for the parasites in 

 the oat fields, and in the wheat fields to the north of town, spending the 

 entire day making this search. ^Ye were unable to find parasites on the 

 Toxoptera. We did find parasites on two other species of aphids, 

 which were on weeds and grasses in the vicinity of the wheat fields. 

 These parasites were subsequently reared and an attempt was made to 

 introduce them into Toxoptera, but the attempt was futile. 



Several oat and wheat fields were thoroughh' investigated and 

 determined not to contain the parasites (Aphidius testaceipes) . We 

 extended our investigation further to include the vicinity of Anson, 

 where one individual parasite was found on the 2oth day of April, 

 by E. L. Barrett. Here we found four or five parasites in brown 

 aphids. Then we went to the fields on the Treekman farm, where 

 we found a few scattering individual brown aphids and the aphids 

 literally destroying the wheat. On the Rarick farm, northwest of 

 Mayfield, we found several parasites. However, since the parasites 

 were not present in the fields northeast of Wellington, and especially 

 those which we examined carefully, we decided that we would go to 

 Medford, Oklahoma, where the parasites were abundant, secm-e a lot 

 of them, bring them to these fields, and attempt an introduction. Ac- 

 cordingly, on the morning of May 4, we proceeded to Medford by 

 automobile, for the purpose of securing the parasites. Driving on to 

 South Haven and across to Caldwell, both wheat and oat fields were 

 heavily infested and in danger of being destroyed. Just south of 

 Caldwell we found wheat fields ver}- heavily infested and beginning to 

 show signs of dying. The change for the worse since the 27th of April 

 was very evident. A careful search in these fields indicated that the 

 parasites had not yet reached them. In some of the wheat fields the 

 plants were eight to ten inches tall, but were dying, and dying fast. A 

 large number of the aphids were collected in this vicinity and taken to 

 Wellington, where no parasites were reared from them. We continued 

 our investigations south and west of Caldwell to Renfrow, the fields 

 being more and more seriously infested, and more seriously damaged, 

 the farther we went. The oats were beginning to take on a red or 

 brown appearance. Oats which were sown in a devastated wheat 

 field just north of Renfrow were practically dead. A few parasites were 

 found on oats and wheat in this field, more than we had found at any 

 place south of the Treekman farm, and more than we had found any- 

 where, other than in the wheat field northwest of Medford. The 

 situation in the vicinity of Medford was alarming; the oat fields were 

 turning brown, as if a fire had swept over them. The wheat fields 

 were just as badly infested as the oats, but the wheat, being larger, 

 infestation did not show to be quite so severe. Many farmers were 



