40 
corn field, now in oats, to more favorable locations, — a migration which 
included all the ants, of whatever age or condition, but in which their 
aphid possessions were apparently sacrificed — probably eaten by their 
owners as a last resort of domestic economy. Not all the aphids of 
the oats field were thus lost, however, but some seem to have been 
transplanted to grasses near by, and others, which acquired wings as 
food began to fail, escaped by flight. Such winged aphids were re- 
peatedly seen to be captured by wandering ants, who took them in 
charge and placed them on the roots of suitable plants. Others, light- 
ing by chance on a corn plant, made their own way down the stalk, and 
thus found a lodgment on the roots, where they were doubtless after- 
wards found and cared for by ants. Nevertheless, the loss of root- 
lice consequent upon a change of crop, altho not complete, must have 
been enormous, only now and then one of the aphis inhabitants of the 
field being fortunate enough to fall upon favorable conditions ; and 
crop rotation remains one of the most efifective means of checking the 
multiplication of these destructive insects. 
