56 CORN AND GRASS. 



maggot lying within. The specimens were received on the 12th of 

 November. 



Looking now over the whole history of this Frit infestation, it 

 appears to me that our customary agricultural treatment is a great safe- 

 guard against anything like cmtomarij attack. 



The fly can infest common Grasses and Corn crops, but as a matter 

 of preference it takes Oats and Barley, and with us (although in the 

 year of bad attack (1888), I had the opportunity of examining many 

 samples of infested plants), I have no personal knowledge of it having 

 been found infesting other crops than Oats ; and also had detailed 

 information from two careful observers (one in Cornwall, and one near 

 Tetsworth) of the marked preference of the Frit Fly for Oats over 

 Barley, even when the two crops were sown together, as with " dredge 

 Corn " (in this case Barley and Oats mixed); or, in another case, 

 where part of the field was in Oats, and the other part in Barley. 



Going on now to cultivation, — with regard to time of Oat sowing. 

 In the ' Elements of Agriculture ' (the Royal Agricultural Society's 

 Text-book on this subject, prepared by Dr. W. Fream), p. 241, we find, 

 " Oats as a Corn crop are almost always sown in the spring, but in a 

 few light land districts they are popular as an autumn sown crop." 

 Also in the table at p. 256, the time of sowing is given as " February 

 to April ; occasionally in autumn, when the winter variety is sown." 



It is obvious that where winter Oats are not sown, the Frit Flies 

 that may be about in autumn do not find their favourite egg-laying 

 plant. They may deposit on wild Grasses or cereals sufficiently to 

 keep the breed from dying out, and they probably do, but there are not 

 great nurseries of infestation in which chrysalids can spend the winter 

 to give us out flies in April. 



Injury, however, from this third brood of the year appears to be 

 very little noticed any more than that of the second, or summer brood, 

 in the Oat heads ; and so long as (from whatever cause) there is no 

 appreciable amount of this second attack to supply flies for autumn 

 laying, and as a general thing the special crop for the use of such as 

 may come is not sown until February or later, there does not seem to 

 me to be reason to fear any really general attack. Still, as when from 

 some unknown cause the infestation appeared in Devon and Cornwall, 

 and some other scattered localities in 1888 and 1889, it showed a 

 power for mishief which called for care and thorough knowledge of its 

 habits ; it has seemed worth while to keep careful watch till we could 

 make out and record its full history. 



For preventive measures against an uncertain attack it is hardly 

 possible to give up time and trouble for special arrangements which 

 very likely may never be needed. But where there is reasonable cause 

 for expecting it in the spring Oats, it is well to remember that those 



