92 
The Bulletin 
length of thorax, compressed and sparsely punctate except near base, 
where it is swollen, coarsely punctate, and shallowly grooved above. 
Thorax slightly longer than wide, sides parallel from base for three- 
fourths their length, then strongly rounded to the constricted apex; 
disc very coarsely and irregularly punctate, the median vitta usually 
broadly dilated at middle, its apical portion very narrow; lateral vittse 
broad at base and with a short oblique branch, their front portion often 
replaced by coarse punetures. Elytra oval, their surface uneven, sides 
gradually narrowed from humeri to apex; striae fine, coarsely and dis¬ 
tinctly punctate; intervals flat, their punctures hidden, and third some¬ 
times feebly base. Humeral umbone and sub-apical callus somewhat 
prominent, often shining. 
DURATION OF LIFE OF THE ADULT 
The adult beetles found in any corn-field during the spring and early 
summer must, for the most part, be adults that matured the previous 
June, July, August, September, and October, as the adults live over 
the winter. (See discussion of hibernation of adults.) Laboratory 
experiments seem to indicate that occasionally, at least, adults might 
be able to live over two winters. We have never been able to keep 
adults through two winters, due, perhaps, to the fact that conditions 
are not normal; but we have been able to keep them through one 
winter and through the next winter until the first of March. 
These beetles were collected June 20, 1910, and represented the 1909 
generation, and must have matured the previous June, July, August, 
September, or October. They were, therefore, from seventeen to twenty- 
one months old when they died. These beetles might have lived longer 
than March 1, 1911, if they had not been disturbed during January 
and February to see whether they were alive. However, a mis¬ 
cellaneous lot of beetles hatched during the summer of 1912 and used 
for egg-laying records during 1913 all died before the spring of 1914, in 
spite of the fact that they were not disturbed. A similar fate awaited 
those adults reared during the summer of 1913. At the present writing, 
November 26, 1915, five out of the 1914 generation are still alive. In 
June, 1913, about 500 adults were marked in various ways to see 
whether any of these adults which undoubtedly represented those 
emerging during the summer of 1912 would be able to pass through 
the winter. None of these marked beetles were recovered during 1914. 
But in spite of this fact the writer believes that occasionally a beetle 
might be able to live through the winter. At least they are able to go 
into hibernation, and it seems only reasonable to suppose that occa¬ 
sionally they are able to emerge from hibernation, although at the 
present time we have no evidence to support this conclusion. These 
might represent the adults which lay only a few eggs during the 
summer (see egg-laying records above). At least, we have not been 
able to assign any other cause to the failure of certain adults to lay 
