12 INSECTS AFFECTING STORED PRODUCTS. 
paper was inserted. The excess of humidity caused by this addition 
induced uneasiness on the part of the larvae, which were now full- 
grown. When, however, the normal degree of temperature was 
produced, the larvae attacked the blotting paper, which happened 
to be placed against the glass, and soon constructed a pupal cell such 
as they probably produce under more normal conditions. One of 
these cells of about typical form is rounded irregularly and measures 
one-fourth of an inch in length by three-eighths of an inch in its 
widest diameter. The pupa, as in the case of the pupae of so many 
other beetles, rests at the bottom of the cocoon on its back. 
Larvae selected during May for the purpose of observing the period 
of the pupal stage transformed to pupae July 16 and to imagos July 
22, or in between five and one-half and six days for different individ- 
uals. Others in a cooler temperature required 8, 9, and 10 days for 
the pupal period. 
Under above conditions (e. g., from June 23 to July 25) the devel- 
opment of this species, from the laying of the egg to the issuance of 
the beetle, covered 32 days. This was during an exceedingly heated 
period and is doubtless not far from the minimum period for the life 
cycle. In another case, where the weather was cooler, comprising 
portions of the months of April, May, and June, the life cycle required 
59 days, or eight and one-half weeks. Three distinct generations 
were obtained, from the first generation of beetles to their children 
and finally to the grandchildren. 
The species does not appear to be long-lived under confined con- 
ditions. Adults, active and breeding, seldom lived longer than three 
months. Doubtless in the open this period can be greatly extended. 
It should be mentioned in connection with the life history of this 
species that upward of a week is required for the beetle to acquire 
the full deep shining brown of maturity. The thorax and the apices 
of the elytra color last, and the latter often remain much lighter 
colored than the other parts. The beetles, however, are active long 
before they have acquired this complete coloration. Hence it happens 
that in most lots of the beetles seen there are many which are not 
fully colored, although otherwise perfect. 
Some other experiments were made to ascertain if the insect is a 
primary feeder upon perfectly healthy dry seed. In hard wheat, 
corn, and beans a few larvae hatched and for a time lived on the meal 
that the imagos cut from the corn, but failed to develop. In softer, 
fresher seed in the field they could no doubt breed freely. 
ENEMIES. 
A single natural enemy was observed in the rearing jars, viz, the 
predaceous mite Pediculoides ventricosus Newp. It occurred in 
April and May. 
