€0 FLIES. 



from a plant or two of wheat. But it is important to 

 know that the same species of maggots can live as 

 maggots in the young corn plants during the winter, 

 and in the summer feed on a totally different part of 

 the plant. In this case spring-sown Barley* is mani- 

 festly safe from attack during its early growth ; and 

 clearing away the masses of wild grass, which often 

 are allowed to grow in strips several feet wide by 

 hedges, would get rid of winter-quarters of the Fly, 

 which frequently may be found especially infesting the 

 corn by these grass headlands. It is often also found 

 to infest patches, or an acre or more, of wet land in a 

 field, where the rest of the crop is free ; and here we 

 get to the point of effect of the state of the land, or of 

 special manure on amount of Fly attack. 



The extent to which the condition, or special treat- 

 ment of land, may influence amount of presence of 

 some kinds of crop infestation, is markedly shown in 

 the case of the Wheat-bulb Fly (see Fig. 47, p. 57). 



In this case the harm is done by the little white 

 legless maggot feeding within the young Wheat plants 

 early in the year, and thus destroying the infested 

 shoot. The presence of the attack is observable from 

 the withering of the attacked shoot, and is noticeable 

 by the beginning of April, or some weeks earlier. 

 About the middle of May the maggots may be found 

 changing to the chrysalis state in or by the destroyed 

 shoot, and some weeks later the hairy greyish Fly 

 appears from the chrysalids. 



But the remarkable point of this attack is that it is 

 especially prevalent after fallow, or bare fallow, or 

 where land has been exposed to the sun, as where a 

 potato crop has been cleared early, or there have been 



* Since writing the above in 1883, 1 was favoured by an observation 

 from Prof. W. McCracken (of the Royal Agricultural College, Ciren- 

 cester), that on the College grounds the portion of the Barley sown in 

 March, 1889, was practically free from injury , that sown on April 

 fith was injured to the extent of 2 per cent. ; and that sown on May 

 3rd to the extent of not less than 20 per cent. — E. A. O. 



