14 
easily. Will you please tell me what you know in regard to the 
matter, and what has been done on this subject." 
Two assistants of the office, Mr. E. P. Taylor and Mr. E. O. G. 
Kelly, visited this neighborhood April 6 to 13, and after a careful 
survey of a large number of farms, selected three for special experi- 
ments, belonging respectively to H. B. Hinman, Edward Finne- 
gan, and Frank Barto. Special observations were also made on the 
underground aphids in fields of corn and oats in comparison, on the 
farm of the F. H. Thompson Estate. 
At the time of this first visit the root aphids were all still in the 
egg stage in the burrows of the small brown ant (Lasius niger 
alieniis). The ants themselves were opening and extending their 
burrows, and the aphid eggs were found in clusters in carefully 
formed chambers about an inch under ground, in varying numbers, 
the maximum observed in a single nest being two hundred and 
seventy-five. The ants themselves had gone as deep as seven and a 
half inches, but no aphis eggs were found deeper than an inch. The 
fields were dry, and plowing had already begun. The soil was well 
pulverized, and many ants' nests had been turned over and covered 
up, but were not much broken up or scattered by the plow. 
The first aphis egg hatched April 9, and several others from 
the same lot hatched the following day. The young as fast as they 
left the egg were placed by the ants on the roots of smartweed 
plants. Many of these weeds were from half an inch to an inch 
high, but many, barely sprouted and not yet out of the ground, had 
been found by the ants, and exposed by burrowing along them. The 
field work at this place was assigned to Mr. E. O. G. Kelly, who de- 
voted his entire time to it for several weeks. 
The weather of April and May was so unusually wet as to in- 
terfere materially with the intended treatment of the experimental 
plats. It also prevented as frequent access to the fields as was de- 
sirable for purposes of inspection, the exact comparison of check 
and experimental plats being indeed delayed until May 31, so long 
a time after treatment in some cases as to impair greatly the values 
of these comparisons. Illustrations of this point will be given in 
some detail in the general discussion at the conclusion of this paper. 
No precise record was kept of the rainfall, but the following memo- 
randa will be of assistance in discussing the experiments. 
A light rain fell April 6, but from the loth to the 25tli — the 
period of plowing — the weather was, on the whole, quite dry. April 
27 and 28 heavy rains fell, but the fields were fairly dry again from 
April 30 to May 8. From the '9th to the 12th it rained hard and 
frequently, and the soil was continuously wet to the 15th, when it 
