GRAMINEOUS CROPS. 103 



many otker destructive species which are plentiful all 

 over the world. The rice weevil is of small size, not 

 more than an eighth of an inch in length, and is well 

 known in the Colonies and India by the characteristic 

 four red spots on the black elytra. This insect is de- 

 structive to Indian corn and wheat as well as rice. 



On the authority of Mr. 0. Whitehead, P.L.S., " C. 

 oryzcB does enormous harm to wheat in Indian granaries, 

 and to wheat while it is being transported in vessels to 

 this country. The admixture of dirt, seeds, and rubbish 

 causes the wheat to heat, which is detrimental to its 

 quality, and at the same time causes weevils to propagate 

 unusually and to materially damage it. Sometimes the 

 cargoes of wheat that have been heated are nearly alive 

 with weevils, causing great waste and heavy loss to im- 

 porters. This loss continues when the bulk is taken to 

 granaries or warehouses where the heat is still evolved, 

 and the weevils revel in it. The amount of loss occasioned 

 by this weevil is estimated at an average of 2^ per cent. 

 Taking the value of wheat exported at £6,000,000, the 

 amount of loss due to this insect in exported wheat alone 

 equals £150,000 " {Nature, vol. 40, p. 841). 



There are two principal fungi that cause disease in 

 the rice crops of India and the Colonies. The first is the 

 smut fungus (C7. carbo) already described ; and the second, 

 Claviceps purpurea (the ergot of cereals and grasses), 

 which wiU be described later in this chapter. 



(6) The Parasites of Rye {Secale cereale). 



The Grain Aphis {A. granaria) has already been 

 described as an enemy of barley, oats, and grasses. 



The Eelworms {Tylenchus deva?tatrix and T. 

 Havensteinii), described in chapter ii., cause considerable 



