No ah Lieb ae ah ae el 
99 
feet wide two adults and a single living larva were dug out, all the fore- 
going being within a foot of the surface. In two large areas turned 
over at the margin of the worst-infested spot, two living larve 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 op- 
erations in the insectary, we have reason to infer the transformation to 
the imago stage during the season of 1890 of the greater part of the 
white grubs in the ground. 
In 1891 the entire field was sown to hemp; but in 1892, three 
years after breaking, it was planted again to corn, and again heavily in- 
jured by grubs. August 25, a general survey of the field showed that 
no part was free from them, and that probably every acre had been in- 
jured 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 worth- 
less 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 (Portulaca) 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 the 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 another 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 
were at this time apparently from two-thirds to three-fourths grown, 
the most abundant species being L. rugosa—the same as that of the pre- 
vious years. 
Tn addition to affording an excellent illustration of the destructive 
capacity of the common white grubs, this record is of special interest as 
evidence that L. rugosa at least will lay its eggs and breed abundantly 
in fields of corn. On no other supposition can we explain the appear- 
ance of such vast numbers of partly grown larve three years after the 
ground was broken from grass in the spring; three years, that is, sub- 
sequent to the latest time at which the eggs could possibly have been 
laid in the grass. It seems very likely that this second lot of grubs 
was hatched from eggs laid in the corn in the summer of 1890 by the 
beetles which came out of the ground in this same field. If this infer- 
ence be correct, it follows that planting to hemp for a year will not clear 
the ground of grubs. 
A somewhat similar inference of a readiness to breed in corn is to 
be drawn from our observations on another plot of about four acres on 
the University farm near Urbana. This field, broken up in the spring 
of 1890 and put into corn, was planted in 1891 partly to corn, and 
partly to oats; in 1892 to oats and corn again, but with the areas re- 
