The Currant Fruit Fly. 189 



From table 6, one can readily comput that 29 per cent of 

 the total number of drops having egg" chambers were cracked 

 compared with 6 per cent fallen cracked fruit without egg cavi- 

 ties. Gooseberry drops with one egg receptacle showed that 

 32 per cent were cracked. Similar data were also obtained in 

 checking up the effectiveness of the poisoned bait spray. Drops 

 with egg chambers obtained from a gooseberry bush treated 

 with the poisoned bait showed that 7 per cent were cracked com- 

 pared with 1 per cent fallen cracked fruit without egg cavities. 

 Gooseberries picked at the end of the season from a check or 

 control bush, showed that 23 per cent of the berries with one 

 egg receptacle were cracked. Cracked currants with egg punc- 

 tures were also observed among the drops and picked fruit. In 

 all probability, the cracking of the fruit was due to the fact that 

 the tissue had been killed in the formation of the egg chamber 

 and in the further development of the berry cracking resulted 

 due to the interference of this dead tissue to uniform growth. 



The first gooseberry dropped from the same bush 5 days 

 after oviposition had taken place and 11 berries dropped before 

 the eggs hatched. The maximum period of dropping occurred 

 on July 2-5, when the larvae which were less than a week old, 

 caused 62 per cent of the fallen fruit. Before the exit of the 

 first larva 78 per cent of the total number of drops containing 

 egg punctures had fallen. 



Currants and wild gooseberries may also drop before or 

 after the egg hatches, or the currants may remain on the bush 

 throughout the larval development. The exit hole of the larva 

 (Figs. 14, H. 15, G.) was occasionally found in currants and 

 cultivated gooseberries which were still adhering to the branches. 



Infested Unfertilized Berries. 



Among the first drops of the season are a large number of 

 unfertilized berries in which the currant fruit fly sometimes 

 deposits its eggs before the fruit falls. Unfertilized gooseberry 

 drops become shriveled, dried and turn black on the ground in 

 about ten days and the larva is unable to complete its develop- 

 ment in such berries. 



