June 1895.] 



INJURIOUS INSECTS AND FUNGI. 



35 



111 about 10 days a white, curved and fleshy grub comes from the 

 egg. This grub has no legs, its horny head is light brown, there 

 are a few small bristles upon the segments near the head and 

 tail. It is nearly the twelfth of an inch in length. It bites 

 away and feeds upon the contents of the grains with its strong 

 jaws until it assumes the pupal state, in which it continues 

 Ironi 8 to 10 da} b, and then the perfect weevil appears and 

 eats its way out of the grain. The various stages of one 

 generation are passed in from 35 to 45 days, depending upon 

 the temperature. In a cold climate there are two, or at most 

 three, generations ; while in hot countries there are continuous 

 successions of generations. Where stored grain is badly affected 

 by weevils, the teinj^erature of the heaps is considerably raised 

 by the heating of the fine refuse resulting from the action of 

 the larva3 upon the grain. In such circumstances, in all proba- 

 bility several generations are produced even in cool climates. 

 The weevils themselves do as much harm to the grain as the 

 larvae. They live upon it, and have been constantly seen boring 

 into grains with their snouts. They h3^bernate during the winter, 

 at least in cold climates, in cracks in the tioors, beams, and walls 

 of the granaries and corn stores, from which retreats they may 

 be seen emerging in swarms in situations facing south on the 

 first sunny spring day. 



The Siiojj/iilus oryzce is not quite so large ns the SitopMlus 

 granaricL It is rather darker in colour and has reddish-coloured 

 patches upon the wing cases. It is furnished with wings, 

 although it does not appear to make much use of them, at least 

 in this country, whereas the Sitopliilus granavia hd^^ only 

 rudimentary wings. The larvae and pupa3 of each species are 

 almost identical, and the history and habits of each are similar. 



Preventive and Remedial Measures. 



Wheat stored in very laige heaps is not so liable to be 

 attacked as that kept in small quantities, because in the larger 

 heaps, air is excluded and gome air is necessary to the weevils. 

 Grain kept in bags or sacks is generally more injured than that 

 in heaps. In India, the natives keep wheat in air-tight pits, and 

 in these, weevils do little or no harm to the grain, although it 

 sometimes remains stored in this way for years. But when 

 the wheat is taken to the "godowns," or granaries, it ,?oon 

 becomes infested with weevils. Grain placed in large heaps 

 must be examined closely from time to time when it is turned. 

 Weevils will be found in the grains nearest the outsides of the 

 lieaps. 



Small heaps of grain should be frequently turned and moved 

 zo that the weevils may be constantly disturbed. 



In these days, when imported wheat containing weevils is 

 distributed throughout the United Kingdom, every granary and 

 corn warehouse is liable to be infested by this insect. Grain 

 should not be kept in sacks in establishments where weevils are 

 known to be present. 



