204 Maike Agricultural Experiment Station. 1917. 



During- the season of 1914, the first oviposition observed 

 in the held was on June 6. Numerous flies were seen depositing 

 eggs on the warm days of June 11, 12 and 13. The last female 

 laying eggs was captured on July 10. The egg-laying period 

 therefore, covered 34 days. 



In 1915, the first oviposition in currants under natural con- 

 ditions occurred on June 9, and the last on July 15. The deposi- 

 tion of eggs in this year extended over a period of 36 days. 



Number OF Ripe Eggs in Ovaries. 



Ovarian tubules mounted in toto dissected from currant 

 fruit flies which were copulating in the field early in the season, 

 show that there were usually five eggs present in each tubule. 

 The lowest tgg in each ovariole was considered mature when no 

 nurse cells were present. When the &gg tubes were treated with 

 hot carbolic acid or clove oil and mounted in balsam on a slide, 

 an unripe egg became clear, while a full grown egg appeared 

 opaque under a microscope by adjusting the mirror and shutting 

 off some of the light. Above the second proximal egg in each 

 tubule is a nutritive or yolk chamber which is filled with a mass 

 of nurse cells. The eggs anterior to the second one, however, 

 are surrounded by nurse cells. The average number of full 

 grown eggs in the two ovaries of 10 specimens captured mating 

 in the field on June 7-8, 1915, was 7. The largest number of 

 fully developed eggs counted in the two ovaries of one female 

 was 17 and the smallest number in another specimen was three 

 (Table 13). 



Number of Ovarioles in Ovaries. 



Each ovary is made up of a variable number of egg tubes, 

 there being usually between 15-18. Table 13, shows the number 

 of ovarioles and ripe eggs in 10 specimens which were copulat- 

 ing in the field early in the season. 



