121 
dred early in May.* In this chamber they lie until August or 
September, when they change to the June beetle, fusca and gib- 
bos , as early as August 11, and others—at least individuals of 
implicita, for example—not before September 17. A small per¬ 
centage of the adults thus formed late in the summer and in 
narly fall, may escape from the earth before the winter opens, 
but this is relatively a rare occurrence, the great mass of the 
generation continuing through the winter in the pupal cells 
within which they originated. They are to be found in winter 
from no more than two or three inches to about ten inches be¬ 
neath the surface. Hence they escape in spring, as already 
described, pairing and laying their eggs for the generation fol¬ 
lowing. 
From the foregoing it will be seen that the white grubs of the 
genus Lachnosterna hibernate in two stages only, those of larva 
and imago, the grubs themselves representing at least two gen¬ 
erations. f 
Cyclocephala, (Plate XI., Fig. 8; Plate XII., Fig. 1 and 2).— 
The white grubs of the genus Cyclocephala differ from those of 
the various species of Lachnosterna in so far, at least, as to 
hibernate in the larval stage, to pupate in May and June, 
and to emerge as beetles in June and July—later"on an aver¬ 
age than the species of the other genus. Pupation is conse¬ 
quently earlier than in Lachnosterna, and the emergence of the 
imago occurs later in the season, the essential difference being 
that adults of Cyclocephala escape from the earth one or two 
months after the completion of their larval life, while those of 
Lachnosterna continue in the earthen cells as pupae and imagos 
about ten months. The difference in the economic application 
of these biographies is not, however, very great, since the period 
of active larval life of Cyclocephala seems to terminate on an 
average only three or four weeks before that of Lachnosterna. 
My detailed notes on the tram formation of white grubs belong¬ 
ing to this genus are but few in number, but as they accord 
with those already given by entomologists, they serve to support 
the common statements concerning the life" history of these 
beetles. 
Our only species in Illinois is C. immaculata , and its larvae 
occur in grass with the other white grubs, and have been 
found infesting corn on sod. Grubs of this species collected in 
grass lands at Urbana, 111., April, 1887, had all emerged as 
adults July 19. Others collected from corn fields April 25, 1888, 
had pupated, at least in part, June 20, and afterwards gave the 
imago—at what date is not now known. In April, 1890, grubs 
* ! rom the fact that the grub of Cyclocephala pupates in May in Illinois. I surmise that 
the above-mentioned larvae belonged to this genus, and were not distinguished from the 
Lachnosterna larvae among which they occurred. 
t, + full particulars upon which the foregoing statement is based, see Seventeenth 
- ktate Ent. Ill.,pp 31-38. To the data there tabulated, I may add the following items noted 
° ru,:)s of fusca collected in corn fields near Champaign. April 16 and 17 and May 
2, had begun to pupate July 18; and those of L. rugosa, taken at the same times and places, 
had formed two pupae at this last date just mentioned. 
