Norman Cunlifpe 133 



granarius (emerged 16. 8. 20); Chalcidae, Dicyclus fuscicornis, Walker 

 (emerged Sept. 1919) and specimens of at least two other genera, at 

 present unidentified. 



SUMMARY. 



1. The adult frit-fly is prevalent in the field throughout the year 

 except for the period November to April. 



2. There are periods of high prevalence, which are probably limited 

 by meteorological conditions. 



3. High prevalence seems to be associated with high temperatures 

 and emergence with rainfall, and should not be associated with any 

 particular brood or generation. 



4. It is very probable that normally four generations are produced 

 in one year and that the fly is double-brooded. 



5. The periods between the emergence of successive generations are 

 about 50 days in spring, 35 days in summer and 230-250 days in winter. 



6. Arrhenatherum avenaceum, Festuca pratensis, Lolium italicum, 

 Lolium perenne and Poa annua can be utilised as host plants in the 

 summer and Alopecurus myosuroides, Arrhenathermn avenaceum, Hor- 

 deum pratense, Lolium italicum and perenne in the winter. 



7. In captivity, the longevity of the imago averages 50 days in 

 spring and in summer. 



8. Ploughing-in and rolUng would only control the pest on heavy 

 land. 



9. Nitrogenous manures are not likely to repay the cost of appUca- 

 tion on average land in England. 



10. The following Hymenopterous parasites are recorded, for the 

 first time, as attacking frit-fly: Chasmodon apterus, Nees, Psichaera 

 (Forst.) spp., Aphidius granarius and Dicyclus fuscicornis. Walker. 



REFERENCES. 



(1) Aldrich, J. M. (1920). Journ. Agric. Res. Washington D.C. xvni, p. 454. 



(2) Baranov, a. D. (1912-13). Zerastvo of Govt, of Moscow, pp. 83-101 (Abstract 



in Rev. App. Ent. i, p. 214). 



(3) (1914), Ibid. Moscow, p. 112-130 (Abstract in Rev. App. Ent. n, p. 371). 



(4) Cameron, A. E. (1913). Journ. Econ. Biol, vm, p. 159. 



(5) (1918). Trans. Roij. Soc. Edin. Ln, Pt. i, No. 2, p. 37. 



(6) Carpenter, G. H. (1901). Eco7i. Proc. Roy. Dub. Soc. p. 147. 



(7) (1914). Ibid. pp. U2-5. 



(8) CoLUN, J. E. (1918). Ann. App. Biol, v, No. 2, p. 81. 



(9) Criddle, N. (1916). Agric. Gaz. Canada, m. No. 6, p. 505. 



