36 BULLETIN 1428, U. S. DEPAKTMENT OF AGKICULTURE 
Mesothorax and inetathorax subequal, each with two transverse rows of 
six small setae on tergum and each tergal margin with about nine setae. 
Preeplpleurum and postepipleurum well developed, preepipleurum of meso- 
thorax bearing a large spiracle, hypopleuruni with prehypopleural and post- 
hypopleural chitinizations. Presternum, a larger sternum, a faintly indicated 
sternellum, and a well developed poststernellum present. Presternum with 
three setae on each side, sternum with four parts of setae and with a faintly indi- 
cated sternal plate. Sternal plate of mesothorax subrectangular and about 
twice as long as that of the metathorax which is quadrate. 
Legs five-jointed, chitinized, tarsus and claw fused, tarsus with one seta, 
other joints each with several setae. 
Abdominal segments dorsally divided into prescutum, scutum, scutellum, 
and postscutellum. Prescutum with six small setae. Scutum with a pair of 
setae. Alar area large, bearing a bifore spiracle, a small fleshy papilla, and 
one long, two smaller, and several minute setae. Epipleural lobe bearing two 
long, three smaller, and several minute setae. Hypopleural lobe bearing one 
long and three small setae. Coxal lobe bearing five setae. Sternum large, 
with two pairs of setae ; sternellum without setae. 
THE PUPA 
Pupa uniformly creamy white in color ; length from 7 to 10.5 mm., width 
from 2.5 to 3.5 mm. 
Plead subquadrate, provided with about 12 pairs of setae ; clypeus with two 
pairs of setae and labrum with three pairs. 
Prothorax subquadrate, provided with two pairs of anteromarginal, eight 
pairs of lateromarginal, two pairs of posteromarginal, and usually three pairs 
of dorsal setae. 
Mesonotum and metanotum usually each provided with two or three pairs 
of minute, dorsal setae. 
Abdomen with nine distinct dorsal tergites, the ninth being very much re- 
duced and terminating with a pair of short, chitinized, pleural spines. Ven- 
trally the ninth segment bears a pair of prominent fleshy processes. The 
tenth abdominal segment is small and ventral. 
Median area of abdominal tergites 1 to 8 each provided with a pair of setae, 
lateral area of each tergite with a pair of setae, and pleural areas with a pair 
of long setae and several minute setae. 
Tips of wing pads usually attaining the fifth abdominal segment ; tips of 
metathoracic tarsi extending to tips of wing pads. 
RESISTANCE TO STARVATION 
The adults of the cadelle are fairly resistant to starvation even 
under normal conditions and particularly so when kept at a mod- 
erately low temperature. Adults kept in a warm room, with an 
average mean temperature of about 68° F., survived without food 
for 52 days. Others kept without food in a refrigerator, with a 
temperature ranging from 40° to 50° F., survived for a period of 
184 days. 
The larvae are very resistant to starvation, much more so than the 
adults. Of a small lot of larvae kept without food at room tempera- 
ture, half of them survived for 4 months, several for 9 months, and 
one for 10 months. Another lot of larvae were placed without food 
in a refrigerator with a temperature ranging from 40° to 50° F. ; 
10 per cent of these w T ere still alive after 24 months of starvation, but 
succumbed soon thereafter. 
With such powers of resistance to starvation it is easy to see how 
the cadelle is able to exist over the sometimes considerable periods 
that the grain bins are empt}^. 
RESISTANCE TO LOW TEMPERATURES 
The eggs and pupae of the cadelle are rather easily killed by low 
temperatures and these two stages are never found during the win- 
