110 Observations on the Habits o/Oscinella frit 



a few plants were potted out, covered with the ordinary chimney cage 

 and kept, for the experimental period, in the insectary. Abundant mois- 

 ture, and food in the form of cane-sugar, were supplied. 



The sexes were easily identified under the binocular microscope, the 

 flies being tubed separately and, when necessary, rendered temporarily 

 immobile by means of a wisp of cotton-wool. The parent flies were un- 

 doubtedly of various ages and probably some of the females had com- 

 pleted oviposition. 



The data obtained from these breeding experiments are detailed in 

 Synopsis I. 



Synopsis I. 



Figures in columns 4—8 refer to the number of days after date of infection (15. 5. 20). 



To avoid confusion between individuals of the consecutive genera- 

 tions, the parent flies were removed from the cages before the emergence 



' Examination of the cages after emergence had ceased showed that larvae from very 

 young tillers pupated either in the tiller, in the sheath, or in the soil (one case). Larvae 

 in main shoots pupated in the gallery near the top. This is in accordance with field observa- 

 tions, pupation in the soil being rare. In the first cage of spring oats, six puparia were 

 found (flies dead in four) in four main shoots, only one of which showed normal signs of 

 attack. The blades were only partially cut and remained green. 



In the case of the barley two puparia (flies dead) were found on examination after 

 67 days (from date of infection). One larva bored through the stem of an oat plant and 

 pupated on the external surface immediately below the exit hole after 30 days, the fly 

 emerging after 45 days. 



A pupal period averaging 16-5 days was noted in the case of larvae in oat stems 

 brought in from the field, potted and caged. In four cases puparia were exposed and the 

 following data obtained : 



Larva pupated 8. 6. 20 $ emerged 25. 6. 20 i.e. after 17 days 

 9. 6. 20 (? „ 27. 6. 20 „ 18 „ 



13. 6. 20 ? „ 28. 6. 20 „ 15 „ 



„ 13. 6. 20 c? „ 29. 6. 20 „ 16 „ 



O. frit was bred from Browich wheat grains, flies emerging on 12. 8 20- Samples of 

 eleven other varieties failed to yield the fly. 



