296 HOUSEHOLD INSECTS 



wing covers are plainly striated and the antennae end in 

 three large, long segments which form the so-called "club" 

 of the antenna. When the beetle is at rest, the head is 

 withdrawn into the peculiar hood-shaped thorax. The 

 larvae are white, cylindrical, and when working in their 

 burrows assume a curved attitude like a miniature white 

 grub of a May beetle. The mouth parts are dark col- 

 ored and contrast plainly with the head. The pupae 

 which transform in the burrows made by the larvae are 

 white. 



The yeast cakes referred to in the foregoing were kept 

 in a steam-heated room. This was in March and the 

 room often became quite cool at night so that the tem- 

 perature was rather uneven. Under these conditions, 

 the pupal stage lasted about two weeks (16 days). Very 

 little, if any, attempt is made to form a cocoon. The 

 larvae seem to form more or less of a cell in their burrows 

 and then transform without making a cocoon. The life 

 history from egg to adult occupies about two months, 

 and there may be four or five generations in a year in a 

 heated building. 



The larvae (Fig. 102) of this beetle are almost omniv- 

 orous and they have been known to scientists as old of- 

 fenders of many years' standing. The insect is widely 

 distributed over the civilized world wherever commerce 

 between countries has been carried on. It has been said 

 of the larva that "it will eat anything except cast iron." 

 It has been reported as boring through sheet lead and 

 tin foil. It is particularly in evidence in drug stores, and 

 apparently thrives upon all sorts of drugs, making no 

 discrimination between those that are poisonous to human 

 beings, at least, and those perfectly harmless. Indeed, 



