RELATIONS OF ANTS TO OTHER INSECTS. 



355 



FIG. 212. Membracid (Ccntrotiis sp. ) of 

 Ceylon. (Green.) a, Larva from the right 

 side; b, protruded anal segments of same. 



in the infested hills was then pulled up, exposing the roots on which 

 the aphids were clustered. The little brown ants at once began to 

 carry the aphids 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 when the pots were put in place. 

 Ants were observed over a yard away from the plants that had been 

 uprooted, with root-aphids 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 year this aphis is 

 wholly dependent on the 

 little brown ant for its exist- 

 ence in the cultivated 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 ter- 

 minate here, as will be seen 

 by what follows. 



" So long as the roots upon which the root-aphids are colonized 

 afford 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 females to more succulent roots, 

 but seem to pay 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 corn 

 field to which they had migrated and to note the results of their wander- 

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

 there came a heavy rain storm that flattened the surface of the ground, 

 which was soon encrusted by the action of the 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-aphids giving birth to young on the roots attended by ants. All 

 of these young were very small, at most but a few days old. Other 

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



