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enclosed as to exclude insects from without and to prevent those within 

 from escaping In this inclosed frame three hills of field corn were 

 planted, and on their appearance above ground one of them was stocked 

 with a colonv of Lasius a/ieniis Foist., the small ant which habitually at- 

 tends the root form of this plant louse. The ants made themselves quar- 

 ters about the roots of the corn, and on the 19th of July a number of 

 wingless viviparous female lice with their voung and one pupa were 

 place 1 within reach c^f the ants and were at once carried to the roots <^f 

 the corn bv the latter. (3n the 2 2d of July other root lice, wingless and 

 winged, were placed near the stocked plants and were also carried to the 

 ro )ts. With a view to learning whether or not root lice would of them- 

 selves make their wav to the rc:)Ots of corn, on July 2 2tl, and subsequent- 

 Iv. many specimens were placed at the base of one of the hills not col- 

 onized with ants. They always disappeared, but could not be found 

 afterwards c~>n the roots. The plants with which they vvere placed con- 

 tinued to grow as well as the third hill under the cover which from the 

 first had not been disturbed, and at the close of the summer careful 

 s'jarch did not disclose lice on the roots. The injurious effect of the 

 lice on the infested plants was soon noticeable in their smaller size and 

 less vigorous growth At varic^us times durmg the summer the burrows 

 of the ants along the roots were uncovered, revealing each time the 

 presence of lice. From July 23rd until the first of .August winged lice 

 came from these burrows and were sometimes found on the blades ol 

 corn but more frequently on the inside of the enclosing cloth of the 

 frame. These winged individuals showed no disposition to establish col- 

 onies on the blades of corn, but on the contrary seemed desirous of 

 leaving thp plants as soon as j>ossible. .\\\ were viviparous females and 

 in several cases confined upon the plants, although sometimes inserting 

 the beak and feeding, they died with the ovaries filled with young. The 

 migration of winged lice from the ground was observed at the same time 

 in neighboring fields where on the 27th of July many of- these winged 

 lice, chieHy dead, were found on the blades. A careful search of the 

 roots made at the same time showed that the root form was now rare in 

 situations in which it had done most injury in the spring. Koo^ lice 

 were obscrvt-d on the enclosed corn until the latter part of August, but 

 were not again uncovered until October 7, the ants in the meantime 

 being constantly observed running in and out. On the morning of 

 October 7th, the infested plants were ilug up carefully and carried in 

 doors for careful examination and upon iMie of the roots which had 

 .several times during the season l)een found to support plant lice was 

 found a small colony of ovipari_'Us females, tne only egg-laying example 



