J. E. CuLiJN 85 



will attack the oats and leave the barley; again, in the same Report, she 

 quoted a letter to the effect that oats, drilled about the middle of April 

 on part of a field after roots fed off by sheep, were badly attacked; the 

 other part of the field being planted with barley did not appear to have 

 been attacked. The same discrimination on the part of the fly was 

 noted in Part II of the Annual Report of Intelligence Division of the 

 Board of Agriculture (1911). Ritzema Bos (1894) quoted a case where 

 it appeared that the fly preferred oats to wheat. 



On the Continent, the larvae appear to winter mainly in rye, but 

 also in winter wheat and wild grasses (Baranov, 1914) or rye, wheat, 

 and winter barley (Rorig, 1893); so far as England is concerned little 

 information is available, but the larvae have been found in winter 

 wheat (Ormerod, Report for 1881, and Petherbridge, Ann. Afpl. Biol. 

 1917), W'inter oats (Ormerod, Report for 1889), rye (Roebuck in litt. 

 1918), and in wild grasses, rye-grass. Arena flavescens and Arrhenatherum 

 avenaceum (Edmunds, Rep. Harper Adams Agric. Coll. 1912). Winter 

 wheat has also been known to be attacked in the spring, the flies 

 hatching out at the end of June and beginning of July (Roebuck in litt. 

 1918). 



NUMBER OF BROODS DURING THE YEAR. 



The majority of writers are satisfied that there are three broods, 

 though some Russians consider there may be four or even five in S. 

 Russia. In the laboratory at Kiev four generations were reared 

 (Dobrovbliansky, 1915) as follows: 



Kulagin (1913) considered there to be three broods with smaller 

 intermediate ones, a fourth brood being doubtful and only if weather con- 

 ditions are favourable. Schesterikov (1910) stated that the appearance 

 of the insect is governed by weather conditions. In the Board of 

 Agriculture Report on insects injurious to crops in 1892 (London, 1893) 

 it was suggested that there may be a constant succession of broods 

 dependent upon the state of food plants and the weather, and this view 

 would appear to be supported by the statements made by Baranov, 

 Ritzema Bos, R()rig and Kiihn given at the end of the next subheading. 

 Probably the broods more and more overlap as the season advances. 



