112 
at this time on a count of the grubs found within the length of 
a rod in a fourteen-inch furrow, gave between six and seven 
hundred to the square rod, or at the rate of two hundred and 
eighty-eight pounds per acre. By the time the young corn was 
six inches high about two thirds of it had been destroyed by the 
grubs. The field was not replanted, but about the 10th of June 
it was twice harrowed and sown to hemp. On account of the 
lateness of the season and a midsummer drouth the hemp did 
not grow well, and about a hundred bushels of corn were finally 
taken from this twenty-acre field. July 26, in the part of the 
field which had been worst infested, but three grubs and a single 
pupa were found in digging with a spade twenty hoIe 3 , ranging 
in depth from a foot to twenty-six inches. On the 1st of Sep¬ 
tember a trench four feet long, three feet wide, and two feet deep 
was dug in this same part with the result that only one adult 
June beetle and two long-dead larvae were found. In another 
space eight feet long by three feet wide two adults and a single 
living larva were dug out, all the foregoing being within a foot 
of the surface. In two large areas turned over at the margin of 
the worst-infested spot, two living larvae and one adult were 
taken, the former among the corn roots and the latter about 
ten inches down. 
From these field observations, and parallel extensive breeding 
operations in the insectary, we have reason to infer the trans¬ 
formation to the imago stage during the season of 1890 of the 
greater part of the white grubs in this ground. 
In 1891 the entire field was sown fo hemp; but in 1892, three 
years after breaking, it was planted again to corn, and again 
heavily injured bv grubs. August 25, a general survey of the 
field showed that no part was free from them, and that proba¬ 
bly every acre had been injured more or less.. The damage was 
most serious now on the lower ground, where a tract of about 
two acres bore only a few scattered stalks with ears. Most of 
the corn here had failed to tassel, and much of it had died when 
from eight or ten inches to about three feet high. Patches of a 
rod to two or three rods across on which the corn was dead or 
worthless were to be found in all parts of the field. Nearly all the 
foxtail-grass (Setaria) had also been killed, the roots being cut 
off just below the surface, and even the common purslane ( For - 
tulaca) was similarly destroyed. Most of the grubs were at this 
time within three inches of the surface, and were well scattered 
through the ground, being by no means confined to Ihe hills of 
corn. In one selected area of four feet square, which included 
only two corn hills, eighty-one grubs were dug up, some scarcely 
beneath the surface, and none deeper than three inches. In an¬ 
other area of equal size, containing three corn hills, one hundred 
and thirty-six grubs were found, twenty-one of them in a single 
hill. Here, however, a few had burrowed to a depth of six 
inches. The grubs vere at this time apparently from two thirds 
to three fourths grown, the most abundant species being L. 
rugosa —the same as that of the previous years. 
