37 
and die, and no others can be found to which the aphids may be trans- 
ferred, these are themselves eaten by the workers as a food material 
too valuable to waste. When suffering from a lack of sufficient animal 
food, the workers in our formicaries have occasionally helped them- 
selves to a living pupa of their own species, or have even devoured 
the larvae in their charge, to the last one. The corn-field ant is, in fact, 
essentially a carnivorous insect, and forages actively for animal food, 
especially when it is without a sufficient number of root-lice. Much 
of our breeding-cage work came to naught thru the mysterious death 
of the workers, apparently because their liking for a watery syrup was 
regarded as evidence that this was a sufficient food for them. In the 
field and in the insectary we have seen ants feed at various times and 
under various conditions upon cutworms, carabid larvae, white-grubs, 
dead May-beetles, dead beetles of the corn root-worm, dead grasshop- 
pers, root-lice, myriapods, earthworms, their own pupae and larvae, and 
the pupal envelopes vacated by adults on transformation. Occasionally 
they have been seen injuring corn by hollowing out the soft seed either 
before or after sprouting, and in one case at least they were reported 
by an insectary assistant as feeding on the fibrous roots of the plant. 
An Injury to Corn by Ants 
Under certain conditions, indeed, this corn-field ant may do con- 
siderable injury to corn by a direct, unaided attack. During the cool, 
wet spring of 1905, when the softened kernels lay long in the earth 
without sprouting, and the young plants grew very slowly for a time, 
a field of corn following oats, heavily infested by ants which had no 
root-lice in their possession, was considerably damaged by the ants, 
which gnawed and hollowed out the seed, thus either killing it, or so 
diminishing the food reserve that the plant made a slow and feeble 
start. 
This field of forty acres, lying near Champaign, had been in oats 
in 1904. in corn in 1903, and in grass in 1902. The corn was said by 
the tenant to have been injured by root-lice in 1903, the part worst 
infested yielding not over 22 bushels to the acre, while the remainder 
of the field gave a yield of 55 to 60 bushels. Owing to a report that 
the young corn was being injured by ants, Dr. J. W. Folsom, of the 
University department of instruction, examined it for me May 31, 
digging up sixty-one hills in a way to expose the whole root system. 
Forty-one of these hills were in a part of the field but moderately in- 
fested with ants, and thirteen were in an adjacent part in which ants 
were very abundant. In both cases the hills examined were taken 
as they came, one after the other in the row. Seven hills additional 
were dug up here and there, because of an especially noticeable infesta- 
tion. The corn in this field was unequal in condition, the poorer hills 
being most numerous where ants were most abundant. This unthrifty 
corn was four or five inches high, and of a yellowish hue, while the 
better plants were six or seven inches high, and of a good green color. 
In the less-infested row six hills out of forty-one were infested 
by the corn-field ant, one of them containing also the red house-ant 
