Stored-Grain Pests. 299 
in appearance, but is much smaller and the thorax and abdomen are 
loosely joined. (See fig. 36.) 
The larva of the cadelle is one of the largest of the grain-infesting 
insects and is easily recognized. It is about three-quarters of an inch 
long, fleshy, with the abdomen terminating in two dark horny points. 
The larva is a dirty or chalk white, with head, thoracic shield, and 
the two horny points at end of body black, as shown in figure 37. 
This insect is widespread over the world and is frequently found 
in mills, granaries, and storehouses, where it infests flour, meal, grain, 
etc. Both larva and adult feed on grain and have the destructive 
habit of going from kernel to kernel and devouring the embryo. 
lic. 35.—The dark mealworm: a, Full-grown larva; b, pupa; c, adult beetle. Dis- 
tinguished from the yellow mealworm by the dark brown color of the larva and the 
dull, not shiny appearance of the adult beetle. For true relative size of the larva, 
pupa, and adult compare with figure 34. 
The cadelle often becomes well established in ear corn (fig. 38) that 
has first been injured by the Angoumois grain moth or by the weevils. 
The long slits in corn kernels shown in figure 38 are characteristic 
of cadelle infestation. Were it not for the fact that there is not more 
than one generation of this insect each year the cadelle would be one 
of the most serious enemies of stored grain. As it is it is probably 
the longest lived of the insects that attack stored grain, and fre- 
quently causes severe losses. 
The white eggs are laid in clusters in the food material selected 
and hatch in about 10 days. When the larve become fully grown 
they seek some secluded place in which to transform to the pupa 
(fig. 39), frequently boring into the timbers of the bin or other re- 
