68 
Journal of Agricultural Research 
Vol. XXVI, No. a 
show evidence of their burrowing. The larva often crawls between two 
boards and forms its pupal cell between them, or it may form its cell in 
a hollowed-out kernel of corn. Larvae bred in the laboratory were sup¬ 
plied in most cases with small pieces of cork, and when ready to transform 
they bored into the cork and soon disappeared from sight. The pupal 
form was assumed about nine days after the formation of the pupal cell. 
The pupal stage lasted from io to 15 days in summer with an average 
of from 12 to 13 days. (See Table II.) Apparently the cadelle does not 
overwinter in the pupal stage. 
LIFE CYCLE 
It has been assumed by previous writers that there is but one genera¬ 
tion of the cadelle each year. It appears from the investigations carried 
on at Washington, D. C., that the normal life cycle is as follows: Adults, 
and larvae of all stages, pass the winter in hibernation. The over¬ 
wintering adults lay eggs in the spring that hatch and develop through 
to adults by midsummer. These midsummer adults lay eggs, the larvae 
from which overwinter in all stages of maturity. Many become full 
grown by fall, but probably none transform until the following spring. 
The larvae that overwinter transform in the spring and the emerging 
beetles lay eggs all through the summer and hibernate during the follow¬ 
ing winter. This life cycle applies to the vicinity of Washington, D.|C. 
Farther south, in subtropical and tropical climates, it seems probable 
that development would be more or less continuous and that there would 
be several generations a year. 
