270 INSECTS AND MAN 



begins. The larvae live upon the tobacco leaf, and a very 

 interesting fact is that the size of the adult beetles, into 

 which the larvae eventually develop, depends, not only on 

 the quantity, but also on the quality of tobacco that has 

 been devoured in the immature stages. Experiment has 

 shown that in every case beetles obtained from selected 

 cigars were double the size of those from low-grade tobacco. 

 It will be remembered that the cheese " skipper " is partial 

 to the better cheeses; similarly, the cigarette beetle is 

 somewhat of a connoisseur, for, given a free choice, Claro 

 cigars and Turkish cigarettes are always the first to be 

 infested, whilst cheap-grade tobacco and Madura cigars, 

 kept in the same room, will remain uninfested for years. 

 Apart from the actual destruction of the tobacco leaf, the 

 larvae spoil its aroma and accordingly depreciate its value ; 

 it is some consolation to know that the adults themselves 

 do no damage. This little beetle is most difficult to eradi- 

 cate, and, to that end, an experimental X-ray machine was 

 specially built recently, at great expense, in America. This 

 machine was capable of " sterilising " cigars, on a commercial 

 scale, at the rate of forty thousand a day, voltages of sixty- 

 four thousand to seventy-five thousand and exposures as 

 long as an hour were tried without the slighest effect upon 

 eggs, larvae, pupae, or adults the experiment was a failure. 

 In 1913 an enemy of dry Cuban tobacco was discovered 

 and named Catorama tabaci, but little is known of its life- 

 history as yet. 



GRAIN-EATING INSECTS 



Many beetles are exceedingly injurious to flour, and those 

 most frequently encountered are the meal worm, Tenebrio 

 molitor, the confused flour beetle, Tribolium confusum, 

 and the rust-coloured flour beetle, Tribolium ferrugineum. 

 The earliest mention of meal worms occurs in the works of 

 Thomas Mouffet in 1634, and at a later date Linnaeus 

 gave them their scientific name, which is curiously apt, for 



