field. The corn in the infested hills was then pulled up, exposing the 

 roots on which the aphides were clustered. The little brown ants at 

 once began to carry the aphides to new^ quarters, and the next day the 

 latter, some of them full grown, were abundant on the roots of the 

 corn in the pots, although there were none on them w^hen the pots were 

 put in place. Ants were observed over a 3'ard awa}" from the plants that 

 had been uprooted, with root-aphides in their mouths, to all appearances 

 searching for a suitable place in which to establish their charges on 

 the roots of corn. Thus it is that from the laying of the eggs in fall 

 to the last or egg-laying generation of the following 3^ear this aphis is 

 wholly dependent on the little brown ant for its existence in the culti- 

 vated fields, and the farmer can justly charge up his losses through the 

 attacks of the root-aphis to the influences of this ant. But the matter 

 does not terminate here, as will be seen b}' what follows. 



WINGED FEMALES OF THE ROOT-APHIS. 



So long as the roots upon which the root-aphides are colonized afl'ord 

 an abundance of nourishment for them, all will be wingless, but as 

 soon as the roots become tough and woody or dry out there will be a 

 generation of both winged and wingless individuals, the former escaping 

 from the burrows about the roots to fly to other plants, and in all 

 probability to other fields, where they may be found on the leaves. 

 The ants usually transfer the wingless individuals to more succulent 

 roots, but seem to pa}' little or no attention to the winged individuals, 

 letting these make their way out and away. But in May, 1887, the 

 writer was able to watch some of these winged nomadic individuals in 

 a cornfield to which they had migrated and to note the results of their 

 wanderings. A field of corn had been planted on May 18. Five days 

 later there came a heavy rainstorm that flattened the surface of the 

 ground, which was soon incrusted b}' the action of wind and sun. 

 Four days afterwards there were freshly-thrown-up mounds of earth 

 about some of the corn plants, and ants were busily engaged in and about 

 these and running up and down over the young corn. On examining 

 these mounds and burrows the writer was surprised to find winged 

 root-aphides giving birth to 3'oung on the roots, attended by ants. 

 All of these 3'oung were very small, at most but a few days old. Other 

 winged individuals were found on the leaves and even on the stems of 

 corn, and when an}' one of these was placed where the ants could find 

 it, it was promptly captured by an ant and transported to the roots of 

 the corn. Observation showed that as soon as the ants running about 

 over the \'Oung corn plants found a winged aphis they made a burrow 

 about the base of a plant, and soon domiciled the wanderer on the root 

 under their guardianship. Then when the aphis began to give birth 

 to 3^oung these were promptly removed to another part of the same 



[Cir. 86] 



