16 
rows. The extremes of treatment in this field, it will be seen, were 
between the part of plat C first planted and the part of plat B 
planted last, these two plats differing in the fact that the late- 
planted part of plat B was harrowed twice more (once with Acme 
and once with toothed harrow) and disked once more than the 
early-planted part of C. 
Observations were made in the Hinman field by Mr. Kelly, at as 
frequent intervals as the weather permitted, during the period from 
May 2 until the planting was finished on the 23d. On May 2, where 
the ground had been merely plowed many young root-lice were seen 
in the field, which the ants were placing on young smartweeds. Five 
ants' nests, all within a space twenty feet square, were explored and 
found to contain from thirty to one hundred and thirty-five ants, 
from twenty to forty aphis eggs — green and about to hatch — and 
from thirty-five to eighty-six young root-lice, all of the first genera- 
tion from the egg. The harrowing of the whole field May 3 and 
4 stirred the weeds about and disturbed the ants and aphids, but 
Seemed to kill neither insects nor weeds. The disk harrow or pul- 
verizer loosened the soil to the full depth of the plowing, and scat- 
tered the ants and aphids greatly. On the 6th of May ants were 
everywhere on and through the soil, and an occasional aphis was 
seen on roots of grass or smartweed, seldom, however, with any ants 
in company. May 13, the ants were generally reestablished in the 
plowed part of the field, and many root-lice were collected from their 
burrows feeding on foxtail-grass and on an occasional volunteer 
plant of corn. Thirty-two ants' nests were dug out on this date, 
each containing from six to one hundred ants. In seventeen nests 
there were no root-lice, and in the remaining fifteen these varied in 
number from two to sixty-five. There were, on an average, twenty 
aphids to each nest containing them, all v/ingless, but many already 
full grown, and all apparently of the first generation from the egg. 
May 18, the corn planted May 8 was beginning to come up, and 
twenty-five hills were dug out. Ants were found in two; root-lice 
in none. 
May 31, a test examination of this field was made by digging up 
in the earliest-planted portions of plats A, B, and C, fifty hills 
from each, and in the later-planted portions twenty-five hills from 
each plat. Although the number of hills dug up wa.^ perhaps too 
small to give satisfactory averages applicable to the entire field, 
Mr. Kelly tells me that the several lots were not taken entirely at 
random, but that each was carefully chosen with the idea of making 
it a fair and sufficient sample of its plat. In digging up the plants 
the whole root system was exposed, and all the ants and all the root- 
