26 DEPARTMENT BULLETIN 1267, U. S. DEPT. OF AGRICULTURE © 
DURATION OF THE ADULT STAGE 
The writers have stated that the adults of the overwintering gen- 
eration of Huetheola rugiceps perish, under natural conditions, by 
midsummer. In the experimental cages numerous beetles of this 
generation not only survived the summer but in some instances lived 
until late in the fall. This late survival possibly was due to the pro- 
tection which the beetles received from the extremes of heat and dry- 
ness to which in nature they are exposed. A heavy mortality among 
the beetles immediately after the mating season is evidenced not only 
by the large numbers of. dead beetles found in the field at that time 
but also.by the fact that corn planted late in the season—after June 
i—is almost invariably much less severely damaged than that planted 
earlier. The longevity of adults in the breeding cages was undoubt- 
edly due to the better care they received, as other adults, confined 
in similar cages but left exposed in the open to as nearly natural con- 
ditions as possible, perished in midsummer within a few weeks after 
the cages were started. 
This view is supported by the testimony of others who have had 
experience with this species. Howard (7) mentions a correspondent 
at Canton, Miss., who reported that previous to July 9 he had had 
little difficulty in finding the adults, but after a week of dry weather 
they had entirely disappeared. Sherman (1Z) also quotes a corre- 
spondent who, writing on June 14, reported that, although the beetles 
had been very numerous and destructive in his cornfields, he had 
noticed that within the last few days the dead beetles could be seen all 
about the field. He added that his corn crop had been so completely 
destroyed that the field was plowed up on June 1 and a new crop 
planted a week later but that this second crop remained uninjured. 
Apparently the duration of the adult stage in the latitude of Vir- 
ginia is from 9 to 11 months. The results obtained in experiments in- 
dicate that under exceptional conditions in nature the adult stage 
may conceivably last from a year to 14 months. 
SPECIES LIKELY TO BE MISTAKEN FOR EUETHEOLA RUGICEPS 
Euetheola rugiceps is often associated with other species of scara- 
baeid beetles which may be easily confused with it. Its most constant 
associates are its close allies, Ligyrus gibbosus (De Geer) and 
Dyscinetus trachypygus (Burm.). For this reason these two species 
will be considered in somewhat greater detail than the remaining 
forms. 
LIGYRUS GIBBOSUS (De Geer) 
The life history of Ligyrus gibbosus is essentially the same as that 
of Huetheola rugiceps. The larve of L. gibbosus develop more 
rapidly, consequently the adults of the new generation appear earlier 
in the fall than those of /'uetheola rugiceps. ‘The writers have never 
found L. gibbosus injuring corn in the field. nor could it be induced 
to feed upon corn in breeding cages. 
LARVA 
In general form, size, and coloration the larva of L. gibbosus re- 
sembles that of Z. rugiceps. As in the latter the fully chitinized 
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