HOUSEHOLD INSECTS 271 



it means a miller who shuns the light. The female beetle 

 lays her white, bean-shaped eggs in flour, bran, or other 

 similar substance which will form a suitable food for the 

 larva. Each egg is about one-twentieth of an inch long, 

 and may be deposited alone or in a batch with others ; in 

 any case, it is covered with a sticky secretion, so that 

 particles of flour become attached to its surface and form a 

 complete covering. The larvae emerge in about a fort- 

 night ; at first they are creamy white in colour, but later 

 they turn yellowish and waxen-looking. In about three 

 months, during which they feed voraciously and undergo 

 at least a dozen moults, they reach their full growth and 

 are about an inch long, and in this state they hibernate 

 through the winter, turning to pupae in the spring. The 

 pupal stage lasts a fortnight, and the whole life-cycle 

 occupies practically a year. 



The two beetles of the genus Tribolium are so similar 

 to one another that they are often confused ; ferrugineum 

 is the commoner in Britain, confusum is more often met 

 with in America. In appearance they closely resemble the 

 adult meal-worm beetle, but are much smaller, being rarely 

 longer than one-sixth of an inch. Their food consists 

 mainly of ground cereals such as flour, oatmeal, etc., but 

 they have also been known to damage ginger, cayenne 

 pepper, baking powder, orris root, dried peas and beans. 

 Under favourable circumstances the life-cycle is completed 

 in five weeks, so there are several generations in a year. 



Beetles are not the only household insects with a par- 

 tiality for ground cereals; the larvae of the meal moth, 

 Pyralis farinalis, feed on cereals in any state, also on 

 other seeds and dried plants. The adult moth measures 

 about an inch from tip to tip of its wings, which are 

 beautifully shaded with reddish brown and white. 



